Unlocking Everything In The Binding of Isaac (Repenting Update!)

This is not your ordinary "list all 637 achievements and their descriptions" guide. The achievement descriptions of The Binding of Isaac are sometimes incredibly vague so I made an in-depth method for unlocking every single item, character, trinket, floor, etc in The Binding of Isaac: Rebirth, Afterbirth, Afterbirth+, and Repentance. The game does well with giving an achievement for every in-game unlock so you will also fully complete the game by getting every achievement and following this guide. Good luck!

Warning: This guide is made for Repentance so details listed here may be incorrect if you have an older expansion of the game.

Introduction

Hi, I am a big fan of The Binding of Isaac: Rebirth (I have 719 hours in the game as of writing this) and I tried my best to fully complete this game without the use of any guides or wikis. I actually got pretty far but came to the conclusion that completing this game is too big of a task to do on pure self-discovery alone. Now that I have 1,000,000% (and am on my way to Dead God), I discovered how useful having a guide is to completing this game. I also noticed that most steam guides and wikis are a bit... lacking in terms of offering advice or methods to various unlocks.

In their defense, a good chunk of Isaac's unlocks and their descriptions are really self-explanatory, but not everything is and I can imagine trying to unlock all 637 achievements (or Secrets as I will refer to them) can be really overwhelming for a new player. So I'm going to go over every single Secret and its unlock method listed in the order that Steam lists them. This guide also serves as an achievement guide as every Secret has and achievement and vice versa.

This guide does SPOIL EVERYTHING so explore at your own risk. I attempt to avoid or hide random spoilers in unrelated Secrets, but you should use Ctrl + F (or whatever it is on Mac) to find a specific Secret if that's what you're here for. This guide makes liberal use of grouping various Secrets together so if you cannot find a specific item using Ctrl + F; try searching for it's category (the specific location/boss in question for example).

Words of note before we start though:

1. To address the elephant in the room, this guide is NOT fully updated for Repentance. I will be updating the guide periodically with some more important Repentance stuff, but don't expect a total overhaul on this guide for a fair bit of time. That being said, the vast majority of Afterbirth+ Secrets translated to Repentance pretty directly.
   
   
2. Isaac is a fantastic game but getting to 110%, let alone 1,000,000% or getting to Dead God, is not for the faint of heart and requires a large amount of time commitment. Even with the guide, I could still foresee fully completing Isaac taking an inexperienced player anywhere from 250-300 hours of playtime. Unless you are dedicated, I would just stick to the various Endings, Completion Marks, and consider Platinum God your completion goal.
   
   
3. You should try to play in Hard or Greedier Mode pretty much 100% of the time if you're in hardcore completion mode! There are many, many Secrets tied directly to doing everything in Hard Mode. The difficulty curve that comes with playing only on the harder modes is rough (and optional), but it can save you much pain in the future as Isaac already takes a long time to complete.
   
   
4. Go into your options and turn on the Found HUD and Extra HUD. These are extra display elements that show you your current stats and recently picked up items. Both of these are massively helpful throughout your runs. There's also some other helpful options in that menu, but these two are the most important.
   
   
5. I won't act like this guide does the best job at explaining every facet of The Binding of Isaac. There are much better places for general information on the game such as
   the wiki[bindingofisaacrebirth.gamepedia.com] or other steam guides I wish I knew about prior to completing this game. My personal favorite being The Bindening™ (link below). As for myself, I am just throwing my own hat in and not attempting to be the "new definitive Isaac guide" or anything like that.
   https://steamcommunity.com/sharedfiles/filedetails/?id=1441000071

Prologue: Keywords

Feel free to skip this if you know how to play, but there are some keywords I use throughout the guide that should be explained ahead of time just so you know what the hell I'm talking about (assuming you are brand new to the game). These words will usually be capitalized despite not being a name or specific item, enemy, etc. If a keyword is not capitalized later on then that's probably a mistake, my bad.

Secret - Another word for achievement. Unlocking literally any achievement in Isaac will put a piece of paper to the screen saying what you unlocked. I assume the game calls these Secrets because said piece of paper refuses to tell you how you unlocked it.

Completion Secret - These have their own section at the ending of the guide because they are Secrets that unlock nothing and merely demonstrate your mastery and/or completion of the game.

Ending - There are 23 Endings in the game, but you'll get every single one of them in the process of finishing even a single Character's Completion Marks so it's not too big of a deal.

Floor - The level you are currently on. There is usually 2 Floors per Chapter until you reach Chapter V, at which then Floor count does not really matter anymore. For example, Chapter III could also be called Floor 5 & 6 while Chapter V can be any variety of Floors.

Chapter - There are 6 main Chapters in the game which you progressively unlock as I will explain in Part 1.

Alternate Floor - Chapters I - IV can gain alternate forms such as Basement becoming either the Cellar, Burning Basement, or Downpour/Dross. They provide a new coat of paint with different enemies and bosses.

Character - It's you and who you decide to play as when you start a run.

Completion Mark - Each Character has a little paper on their Character selection screens and when you pause. As you beat certain bosses or complete specific tasks, you'll unlock Secrets which are displayed in the little paper. I will explain how to get each of these in the rest of the guide, but in case you want to know now, the symbols are as such (from top-left to bottom-right).

Heart = Mom's Heart or It Lives!, Cross = Isaac, Star = Boss Rush, Upside-down Cross = Satan, Photo = ???, Inverted Photo = The Lamb, Brimstone = Mega Satan, Cent = Ultra Greed, Tears(?) = Hush, Tearing of the Paper = Delirium, Knife = Mother, Note = Beast. Any of these symbols being in blood means you've done it in Hard Mode and this is important because there is a Secret for doing all of a Character's Completion Marks in Hard Mode.

Hard Mode - Selected when you choose your Character, this mode makes special multicolored versions of enemies and bosses called champions more frequent, makes curses MUCH more frequent, reduces heart drops, causes Shops to have less items, and so on.

Greed/Greedier Mode - Selected when you choose your Character and operates completely different from the base game of Isaac. The idea is that you fight waves of enemies and then bosses to earn money. Money is then spent in a constantly restocking super shop. Greedier is the Hard Mode of Greed and must first be unlocked by the Greed Donation Machine.

Boss Room/Treasure Room/Shop - Three rooms that all spawn throughout a normal game and serve distinct purposes. There are tons of special rooms in the game, but these are the most important:

• Boss Rooms are where you fight a boss and how you progress onto the next Floor. Bosses are determined by the Chapter you are on and are predetermined at the end of Chapter III, Chapter IV, and then every boss after. At the end of any boss in Chapters I - IV, you receive an item (usually a stat up one).
  
  
• Treasure Rooms are rooms that locked on every Floor other than the first one. Treasure rooms only show up for Chapters I - III and grant free items that are usually more powerful than what you get from Shops or Boss Rooms, but are consequently more varied and not usually just stat ups.
  
  
• Shops are the main way you spend coins. They have pickups and Shop-specific items for sale. Items in the Shop can have their prices randomly become red, which means they are on a 50% sale. Shops also contain the Donation Machine described below.

Devil Deal/Devil Deal Room - Devil Deal Rooms can be found as early as Floor 2 and normally have a high chance (85% - 100%) to show up after the boss is killed. In there, you can buy items in exchange for losing max health. Chances for these rooms can also be raised slightly by certain actions. Devil Deal Rooms will stop showing after Chapter IV. Devil Deal Chance drops by roughly 40% each under these two conditions. The two conditions are:

1. You take "red heart" damage in the current room you are in. Note that soul hearts, black hearts, and any other form of health are not included in this and can be used to shield your Devil Deal chances.
   
   
2. You take "red heart" damage at any point on the Floor. This effectively means that taking "red heart" damage your first time in the Boss Room will plummet your Devil Deal chances to almost single digits.

Angel Room - If you fulfill the conditions to get a Devil Deal Room and then ignore it you will get a chance to get an Angel Room. Afterwards, when a Devil Deal appears on a following Floor, you will get an Angel Room instead. Angel Rooms give their own special items and they are completely free to boot, but are arguably not as good as Devil Deal items.

Secret Room - There are 1-2 of these rooms on every Floor and are found by bombing the middles of walls. These rooms can have enemies, items, coins, or literally nothing. Secret Rooms need to be connected by at least 2 other rooms and none of the rooms connected can have objects or gaps in the way. There are also Super Secret Rooms that are never connected to any room and are usually off in some random corner or near the Boss Room. Neither type of Secret Room can ever be connected to a Boss Room.

Planetariums - After being unlocked, these are incredibly rare rooms with special items that cannot be found elsewhere. Your chance to get a Planetarium is initially 1% and if spawned, they'll be a separate room like a Treasure Room needing a key. There are a few items that increase Planetarium chance, but the biggest way is to not enter Treasure Rooms at all. This increases Planetarium chance heavily.

Donations Machine - There are 2 of these in the game, one in normal Shops and another at the end of Greed Mode. Many Secrets are tied to the filling of both of these up to 1,000 coins.

Challenge - While on the main menu, you may notice the Challenges menu. I'm making a section at the end for describing how to unlock and beat every Challenge because unlocking a Challenge and the item you unlock for beating it both count as Secrets.

Transformation - There are ways to upgrade your Character in a run beyond just items and pickups. The most notable way is a Transformation. Upon picking up a series of (usually 3) items or effects, you gain a permanent upgrade for free. These items or effects typically have a theme (Guppy, Mushroom, Flies, etc) and are needed for some Secrets.

Part 1: Unlocking Floors (1/2)

I know I said I would keep everything to the order that Steam lists the Secrets, but I am making a few exceptions to this. These being Completion Secrets, Challenges, Floors, and Character Secrets. These need their own sections in order to make this guide even slightly cohesive.

I'll start with Floors & Characters as these are the first things you should focus on while playing through The Binding of Isaac. I don't recommend seeking out any other kind of Secrets until Floor & Character Secrets are done. Chances are you will unlock some things before all of the Floor & Character Secrets are done, but it's impossible to do most things without these Secrets first.

The Womb
Chapter 4 - The Womb unlocked.
When you first play The Binding of Isaac: Rebirth you will only need to make it through the first 3 Chapters. The boss of the Depths II will ALWAYS be Mom and defeating her gives you your first Ending and unlocks Chapter IV for subsequent runs. You take full heart damage from everything at Chapter IV onwards.

It Lives!
You're future's past awaits.
After unlocking The Womb, you'll be able to make it all the way to Womb II where the boss will (much like Mom) always be Mom's Heart. Each time you beat it, you'll get a new Ending and Secret up to 11 times. After the 11th time, Mom's Heart will permanently transform into It Lives!. Beating it allows you to progress to either of Chapter V Floors. The transformation to It Lives! does not change any Completion Marks or Secrets related to defeating Mom's Heart outside of making them slightly harder.

The Polaroid & The Negative
Unlocked new items.
These 2 items are unlocked by beating the boss for The Cathedral and Sheol 5 times each respectively. When either The Polaroid or Negative are unlocked, they will appear as the boss reward for defeating Mom instead of a generic item. You then can choose one and only one. Opening the chest that spawns after completing The Cathedral with The Polaroid in hand will take you to Chapter VI: Chest. The same thing can be done with The Negative and Sheol's chest, which will take you to a different Chapter VI: Dark Room. Having the wrong one of these items for their respective chest will end your run right then and there. Both of these items also actually have powerful effects so it's worth it to pick carefully even if you're not aiming for either Chapter VI.

Angels
They are waiting.
As soon as you get to either Chapter VI Floors, you may notice a giant, locked golden door that isn't needed to fight the boss of the Chest or Dark Room. Upon clearing either Chapter VI, you will get the "Angels" Secret, which unlocks 2 hidden boss fights. If you bomb or explode the angel statue in any Angel Room, you will start a fight with either Uriel or Gabriel as a boss. You may have fought the Angels before getting this Secret via Boss Rush. Each one will drop a Key Piece upon death in an Angel Room. If you kill both of them you will form a complete key that can be used to unlock the golden door in Chapter VI where you then fight the true final boss... of Rebirth that is.

Boss Rush
Not a Secret.
The Boss Rush is an optional fight you can take on for a Completion Mark. You access the Boss Rush by defeating Mom in under 20 minutes, at which then a hole will open up in her boss fight arena. Here, you can choose a free item out of a few choices and then will fight 15 waves of bosses from Chapters I to IV. This is very challenging and requires a lot of preparation so be wary. You can always check your current time in your run by pressing TAB on the keyboard.

Blue Womb
Unlocked a Hidden Chapter.
After you've beaten Mom's Heart 10 times, you must beat her or It Lives! in under 30 minutes. Then you'll be able to access a new Floor. Much like with Boss Rush, a hole opens in the arena that takes you to a new Floor known as ??? or the Blue Womb. You will get 2 Treasure Rooms, 4 gold chests, and a Shop, and trust me... you'll need it.

New Area, Delirious, and Lil' Delirium
Unlocked a new area.
Completing the above area once will give you a new Ending. After that, clearing it gives a 100% chance to find a Void Portal in a room above the boss arena. ???, The Lamb, and Mega Satan also grant guaranteed Void Portals, and other endgame bosses have random chances for it. Going through the Void Portal will take you to The Void, a massive Floor with many Boss Rooms containing bosses. One of these Boss Rooms, at random, has a chance to be the true endgame boss for Afterbirth+. Defeat this brutal boss fight and you will unlock the Delirious Secret as well as Lil' Delirium.

A Secret Exit
Complete ??? 3 times.
Once you've completed the Blue Womb 3 times, you'll unlock a strange door that appears at the end of any Floor in Chapters I - III. These rooms will take you to a set of Alternate Floors with entirely new enemies, mechanics, and bosses that are more difficult than the regular Floors.

The door in Chapter I requires a key and will take you to the Downpour. The door in Chapter II requires 2 bombs and will take you to the Mines. The door in Chapter III will deal 2 full hearts of damage to you and can kill you. This one takes you to the Mausoleum. Swapping between this alternate path and the main path will advance the Floors faster than usual.

For example: Leaving from Downpour I to the main path will put you in Caves I.

Part 1: Unlocking Floors (2/2)

The Corpse and Rotten Hearts
Enter the Corpse...
In Chapter I: Downpour, there will be a room with a mirror and a special indestructible white fire. If you touch the fire, you will temporarily become The Lost and can go through the mirror. Bombing the mirror destroys it forever. When in the mirror world, you will need to make your way to the Treasure Room where you will pick up Knife Piece 1.

In Chapter II: Mines, if you have the first Knife Piece, you will find these yellow floors buttons that you can step on. A special room will have a mine cart that needs are 3 buttons to be pressed. Once you do, you can enter the mine cart and go to a special tunnel where all of your items but what you started with are gone. At the end of this tunnel is Knife Piece 2, but be careful. Once you pick up the piece, a monster called Mother's Shadow will begin to chase you. She does a full heart of damage and moves slowly but occasionally charges with an audio cue. The tunnel will be filled with all sorts of puzzles and traps that you must navigate while continuously dodging the Shadow. A tip for this is that Mother's Shadow moves back a bit before charging so it's okay to stand still and just move slightly after she begins the charge in order to escape a tight spot.

Lastly, in Chapter III: Mausoleum, you will fight an alternate, harder Mom fight. If you have the full knife after defeating her, you'll see a flesh door that you must shoot the knife into the door. You will then fight a harder version of Mom's Heart with new patterns (note that this isn't It Lives!). If you do kill her heart, the room will grow dark and you'll be able to enter Chapter IV: The Corpse. This area operates like The Womb, no Treasure Rooms and all, but has entirely new enemies and bosses. At the end of the Corpse is a nightmarish fight that counts as a Character Completion Mark.

A Strange Door
Where could it lead to?
Once you defeat the boss of the above area, you will unlock this Secret. Now at the end of specifically only the main path Chapter III's second Floor, you can find an odd-looking door. Complete the floor as normally, but look for a skull with an "x" on it. Blow this skull up and you'll get a The Fool tarot card. DO NOT USE IT until you fight Mom. Then, after defeating her, grab either The Polaroid or The Negative and use The Fool to avoid being trapped in her arena (any other method of teleportation also works here). Go to this odd-looking door and touch it to put either The Polaroid or The Negative into the door to open it.

After this, you'll enter Mausoleum II and complete it as usual. However, instead of there being a boss, you will be forced to pick up Dad's Note. This instantly begins the Ascent. The Ascent will have you go through smaller versions of the Floors you already completed in reverse order. You start at the Boss Room and must head to the starting room. The Boss Room and Treasure Rooms are preserved from earlier (use this to cheese Planetariums), but otherwise all rooms are different. As you ascend higher, you will come across Tainted enemies, which are new versions of easier enemies that are boss-levels of difficult. You take full heart damage in the Ascent and get few items so be careful.

Note: The section after this is so damn cool that I beg you to stop reading now and come back here after you've done it once yourself. I DO NOT want be the one who ruins this for you.

Once you've reached Basement I and ascend from there, you'll go... Home. Home is a preset Floor with a few pickups, a chest, and a box in Mom's Room that gives you items. If you sleep on Mom's Bed, it'll become night and the TV in the Living Room is on. Gaze into the TV and you will begin The Final Chapter, a series of MANY boss fights that all result in a Character Completion Mark and the true final ending of all of Isaac.

Greed Mode
Not a Secret.
Greed Mode is an alternate playstyle to the base game that involves fight waves of enemies and the collection of money for everything. There are 6 Floors of Greed Mode followed by a final Floor called Ultra Greed. Here you fight the unique pre-determined boss called Ultra Greed and gain a Completion Mark for defeating him.

Greedier!
New mode unlocked!
Every time you beat Ultra Greed, a Donation Machine called the Greed Donation Machine will spawn and allow you to put any leftover coins you have into it. This machine has a chance to break depending on how many coins you've put in with your specific Character on previous runs. Many Secrets are tied to milestones of the machine, with 500 coins being the way to unlock Greedier Mode. Greedier Mode functions as the Hard Mode of Greed Mode with another unique 2-phase endgame boss called Ultra Greedier. There are unique Completion Marks tied to Greedier mode (bloodied cent); however, you can obtain Greed Mode marks at the same time you get Greedier Mode marks.

Part 2: Characters & Upgrades (1/2)

Unlocking Characters (and sometimes their upgrades) is the very first thing you want to do after you've unlocked all Floors in the game. Having all the Characters is imperative to completing this game as each Character's many Completion Marks make up a good chunk of the items unlocked in this game. Completions Marks are earned for beating various endgame bosses and other events with the specific Character in question.

There are 17 Characters in the game and you literally only start with just Isaac so getting every Character is a bit of a process on its own. Some Characters can also gain new starting items through various means, so I'll be including these here to as there aren't many and unlocking them can make some Characters much more tolerable.

The D6
Isaac now holds the D6!
Isaac himself does not have to be unlocked, but he does get one upgrade that makes him quite a bit stronger. To get this upgrade, you have to unlock the D6 and then Isaac will always start with it as well as adding the D6 to the item poll. To unlock the D6, defeat the boss of Chapter V: Cathedral as ???, whose unlock method is shown below. The D6 allows Isaac to reroll item pedestals he finds, giving him much more agency over his runs.

Magdalene
Unlocked a new character.
Maggy has a very simple unlock with many strategies to it. Simply do as her unlock method on the character select states and have at least 7 red heart containers. The max red heart containers are 10 so you'll need over half max health to accomplish this. The best advice I have is to avoid having too many soul hearts and avoid Devil Deal Rooms like the plague. Angel Rooms often give you HP up items so it's in your best interest anyways.

Maggy Now Holds A Pill!
Unlocked a new starting item.
To get a guaranteed Full Health pill for Maggy, you need to beat the "Aprils Fool" Challenge from Afterbirth+ (see Part 7).

Cain
Unlocked a new character.
This Secret requires that you have 55 cents at any time. This is not nearly as hard as it sounds. You can just not ever spend money and hope that it's enough by the end of your run. While doing this, always visit Shops and Secret Rooms as you may fight Greed and gain a lot of money in doing so.

Cain Holds Paperclip
Unlocked a new starting item.
This Secret requires you to donate 68 cents to the Greed Donation Machine in Greed Mode. He will now hold a new trinket.

Judas
Unlocked a new character.
To unlock Judas, you need to make your way to Chapter V: Sheol (shown in Part 1) and defeat the only boss of that Floor.

??? (AKA Blue Baby)
Unlocked a new character.
Unlocking this Character is the very last thing you do before unlocking It Lives! by having you defeat Mom's Heart 10 times, while It Lives! is the 11th time.

Eve
Unlocked a new character.
Much like Cain, Eve's unlock sounds a lot harder than it actually is. You need to make it through any 2 Floors in a row without picking up a heart of any kind. Having Maggy unlocked really helps with this task since she has a self-heal and the most starting health. You could also wait until a later Floor in your run once you've built up a good supply of soul hearts and attempt to just tank it through. Lastly, playing The Lost or Keeper will automatically get you this character unlock as neither can even pick up hearts.

Eve Now Holds Razor Blade
Unlocked a new starting item.
This Secret requires you to donate 439 cents to the Greed Donation Machine in Greed Mode. This item allows Eve to have a lot more control over the amount of red health she has.

Samson
Unlocked a new character.
Now this Character unlock is actually a little bit tricky. You need to complete any 2 Floors in a row without taking damage. Unlike with Eve, you should attempt to do this with only the first 2 Floors and simply reset if you fail. Most Chapter I bosses are pretty easy so your biggest risk is the rooms in-between the Boss Room. Don't try to explore unneeded rooms, just rush the Treasure Room (optionally) and then Boss Room in that order.

Samson Feels Healthy!
Unlocked a starting item.
To start with the Child's Heart trinket with Samson, you need to beat the "Ultra Hard" Challenge from Afterbirth+ (see Part 7). This Challenge is extremely difficult and since Samson is already a very strong Character; it's advised to not attempt this Challenge until the end of your completion journey.

Azazel
Unlocked a new character.
To unlock Azazel, you need to make 3 Devil Deals in one game. When you are unlocking Azazel, you should enter every Devil Deal you can in order to avoid Angel Rooms and also make sure you have a low amount of red hearts. Low red hearts reduces your chance of losing the Devil Deal.

Lazarus (Unrisen & Risen)
Unlocked a new character.
In order to unlock Lazarus, you need 4 soul hearts at a single time. I do not believe that sin hearts and other temporary health contribute to this but I may be wrong. Some items such as PJs, Dark Bum, and many Angel Room items give you soul hearts or increase your chance of finding them so look for those kinds of items. Otherwise, you can blow up tinted rocks (rocks with Xs on them) and visit Shops in order to find easy soul hearts.

Laz Bleeds More!
Unlocked a new character.
To start with the Anemic item with Unrisen Lazarus, you need to beat the "Backasswards" Challenge from Afterbirth+ (see Part 7).

Eden
Unlocked a new character.
Eden is your very first unlock for beating Mom's Heart. This alone is not much of an issue but Eden also requires a currency to play them called Eden Tokens, with one token per play of Eden. You gain a token each time Mom's Heart/It Lives! is killed and Eden becomes unplayable if you run out of tokens. Eden has no starting items and has completely random stats, trinkets, and items each time you play them.

Part 2: Characters & Upgrades (2/2)

The Lost
Unlocked a new character.
Back in Rebirth, The Lost was a super-secret Character with an insanely complicated unlocking method that required digging through various puzzles the game had. When Afterbirth came out, this method was thankfully simplified to a 2-step process. Step one, unlock the Missing Poster trinket by defeating the boss of Chapter VI: Dark Room with Isaac. Step two, find one of those sacrifice rooms (room with one set of spikes alone in it) and kill yourself on it while holding the Missing Poster. You will respawn as The Lost and unlock him. The Lost has no hearts, cannot gain any, and therefore dies in one hit. This fact is important to cheesing some later Secrets.

Lost Holds Holy Mantle
Unlocked a new starting item.
This Secret requires you to donate 879 cents to the Greed Donation Machine in Greed Mode. This is obviously a lot, but it's worth it as The Lost dies in one hit and the Holy Mantle can remedy that. It's advised that you unlock this Secret before you attempt most Completion Marks as The Lost to save your sanity.

Lilith
Unlocked a new character.
Added in Afterbirth, unlocking Lilith is very straightforward and she's literally a Completion Mark for Azazel, who is arguably the strongest Character in the game. Defeat Ultra Greed as Azazel and you'll unlock Lilith. She cannot shoot tears herself and relies on her Incubus to do damage.

Keeper
Unlocked a new character.
The Keeper, like The Lost, was the secret Character for Afterbirth and literally had a whole ARG tied to him being unlocked within the game (look it up, it's super cool). Anyway, after that whole ordeal, the Greed Donation Machine was given a cap like the normal Donation Machine at 1,000 cents. At 1,000 cents, the Greed Donation Machine blows up and unlocks the Keeper. The Keeper has 3 upgrades, but they are all tied to his Completion Marks so I won't be listing them out of redundancy.

Apollyon
Unlocked a new character.
Apollyon was added in Afterbirth+ and is a little tricky to unlock. It's surprisingly not tied to the unlocking of The Void. Instead, all you need to do is defeat Mega Satan, but as Part 1 showed, that is not the easiest task and takes a bit of time to get to.

The Forgotten
Unlocked a new character.
Oh boy... this is a bit of a process. The Forgotten is the Afterbirth+ secret Character so it's a little cryptic. You must have defeated completed Chapter VI: Dark Room at least once before and then you can begin the process.

Step One: Kill the Floor 1 boss in under a minute (indicated by hearing Mom shout) and make your way back to the starting room. In this room, you'll see a shadow of someone digging something. Bombing the shadow will scare it and drop a broken shovel. Picking it up gives you an active item and a curse that causes Mom stomps to constantly chase you. You can use the shovel to stop the stomps for the current room thankfully. DO NOT drop the shovel in place of another active item as it will disappear once you leave the room.

Step Two: Survive all the way to Chapter III and beat the Boss Rush (time limit does not apply like normal). You should use the shovel during the Boss Rush obviously, unless you want to get the stomps to possibly kill bosses.

Step Three: After beating the Boss Rush you will get the other half of the shovel and cleanse yourself of the curse. Make your way to Chapter VI: Dark Room and find an empty room with patches of ground that look like graves. Stand on one of them and use the shovel and you will unlock The Forgotten.

Bethany
Beat Hard Mode as Lazarus without losing a life.
Bethany is from Repentance and her unlock is self-explanatory. Part of the gimmick with Lazarus is that his extra lives makes him stronger and he can swap between his normal and risen states. To unlock Bethany, you must complete Chapter IV on Hard Mode without ever entering the risen state. Bethany starts with an active item that combines with other actives and uses soul hearts as a currency for her active item.

Jacob & Esau
You're just like your father...
J&E's unlock is very much tied to Repentance's Secrets. As described in Part 1, you must defeat the boss of The Corpse on the alternate path. Once you defeat that boss, you'll unlock this 2-in-1 character where you play 2 people at once. This definitely couldn't get annoying or frustrating!

Part 2.5: ??? (1/2)

This whole section is a spoiler. Complete every Secret in Part 1 and then you may return here:

View Heading, if you dare...

You may have realized that Repentance promises a lot of content on the store page and yet, while the alternate path and new bosses are cool, it's not literally twice the size of Afterbirth like advertised. WELL! Let me tell you about one hell of a little trick the game pulls.

While at Home, opening Mom's Box will unlock the Red Key Secret and give you the item. This only happens once, for future runs read below. You can open hidden red doors with this key and there is actually one in Home. Unlocking this door will reveal a small child that looks like you?

So... Repentance adds an ENTIRELY NEW SET OF CHARACTERS called the Tainted that are alternate versions of the already existing characters. They all have their own playstyles and Character Completion Marks. Suit up, you're in for the long haul if you're at the point now.

Unlocking ???: After your first time grabbing the Red Key, Mom's Box will have a random Mom items so you can't rely on that. Instead, in an Boss Room or Treasure Room you must drop a trinket. Then, during the Ascent, you'll find that trinkets have been transformed into the Cracked Key. This is a consumable that acts as a one-time Red Key. What you do with this is self-explanatory.

Completion Marks: You do need to complete all Character Completion Marks for each Tainted Character, but they operate slightly weird. Each of the following earn only one Secret for the respective Tainted Character:

• Completing both Chapter V's and Chapter VI's. Unlocks a new trinket.
  
• Defeating both the Boss Rush and Hush. Unlocks a new "Soul" rune consumable.
  
• Defeating Mega Satan. Unlocks a new pickup or mechanic.
  
• Completing the Void. Unlocks a new item.
  
• Completing the Corpse. Unlocks a new trinket.
  
• Completing The Ascent. Unlocks a new item.
  
• Beating specifically only Greedier Mode. Unlocks a "Tarot Card?" card consumable.

Unlocking any of the Tainted will allow you to access the alternate character select when starting a run. Unlocking each of the Tainted counts a Secret, so be sure to do that. All Tainted characters are unlocked in the same way, so I'll instead spend this section rating their difficulty levels and going over their playstyles as many of them are... weird. As a note, many of the Tainted start with a "pocket active" which is an additional active item that cannot be lost located in the bottom right of your screen.

The Broken (T. Isaac)
???
Difficulty: Average
The Broken is one of the simplest Tainted Characters, which makes sense since he's Isaac. The Broken loses his D6, but gains a powerful innate ability. Every item pedestal you come across for the entire run will rapidly swap between 2 different choices. You can take one, but never both. This gives you EVEN MORE agency over your run than Isaac somehow. The downside? You have an inventory you swap through and you can only hold 8 passive items with it. Any others you pick up will replace previous items.

The way to play The Broken well is contrary to what you might think. Stat up items are helpful at the moment, but what you need to focus on is strong synergies and gimmicks. You can easily make these synergies due to items alternating, but having 8 passives that all provide small stat ups is a good way to get killed. Also, items that drop pickups as well as HP ups aren't lost when swapping items so those are always free to swap out.

The Dauntless (T. Magdalene)
???
Difficulty: Tricky
The Dauntless has 4 hearts and Yum Heart and she passively receives double the healing from all non-pickup sources. The catch is that all hearts but your last 2 "leak" and will drain to empty over time. Additionally, touching enemies will do a high damage melee attack that drops temporary hearts if the enemy dies to it.

If you've ever liked the high HP Maggy has but wanted something to use it for then I have news for you. With The Dauntless, you need to be fast. Fast to pick up dropped hearts, fast to not waste health, and fast to figure out how to best use healing items. Normal enemies are pretty easy with The Dauntless, but the HP management becomes urgent during bosses that don't take as kindly to your hugs.

The Hoarder (T. Cain)
???
Difficulty: Unknown
Secrets yet to be uncovered...

The Deceiver (T. Judas)
???
Difficulty: Chill
The Deceiver operates like ??? in that you cannot have red hearts. You do have better rounded stats that Judas, but lose the Book of Belial. Instead you get the pocket active Dark Arts; which allows you to become the anime nerd you always wanted to be by slowing time and making you invulnerable for a few seconds. Any enemy or tear you pass through in this state will then get slashed once Dark Arts wears off and at the end there is an explosion that does large damage.

The Deceiver can be pretty easy due to the power of Dark Arts. Early on, use it to kill enemies easily and take little damage. Then, as you go later into a run, use the fact that you get a temporary damage up equal to the amount of things you slashed to punish more bullet-spammy bosses. As long as you can manage having no red hearts, The Deceiver makes one of the easier Tainted to play as.

The Soiled (T. ???)
???
Difficulty: Unknown
Secrets yet to be uncovered...

The Curdled (T. Eve)
???
Difficulty: Unknown
Secrets yet to be uncovered...

The Savage (T. Samson)
???
Difficulty: Chill
The Savage is a character that encourages you to play stupidly. You lose Samson's Bloody Lust, but as you deal and take damage from enemies you become angrier. At full rage, you whip at a sword (jawbone?) and get a massive speed and damage boost. This sword annihilates most enemies and possesses all properties of The Forgotten's club.

This character probably exists as a stress reliever after playing some of the more "unique" Tainted. Your rage lasts as long as you keep killing enemies, so it's often easy to chain 4-5 rooms together and clear them in no time. The only downside is that you can't control when the rage happens, but even so the bonus damage isn't bad for bosses. Just don't get so caught up in the rage that you play too stupid.

Part 2.5: ??? (2/2)

The Benighted (T. Azazel)
???
Difficulty: Unknown
Secrets yet to be uncovered...

The Enigma (T. Lazarus)
???
Difficulty: Unknown
Secrets yet to be uncovered...

tHҽ Cαρɾιƈισυʂ? (ꋖ. ꑀꀷꑀꃔ)
!!!!!!!!!!!!!
dIFFICulty:dIFFICulty:dIFFICulty:dIFFICulty:dIFFICulty
DΛMΛGΣ ЯΣЯӨᄂᄂƧ ΣV3Я;ƬΉIIП!?!

The Baleful (T. Lost)
???
Difficulty: Agony
Oh boy it's everyone's favorite Character! The Baleful is a very powerful Character with one very tiny, insignificant catch. NO HOLY MANTLE. Yes, you must play The Lost, but be damn near perfect. You do maintain the other perks of The Lost and have a radically increased chance to find Holy Cards (one-time use Mantles), but it's still a game of perfection.

So what's the upside? Well outside of The Lost's flying, spectral tears, and free Devil Deals; you also get better starting stats. More importantly, bad items are sometimes rerolled to better items and you can't get useless items like HP ups. In fact, you can't get anything of that type. The Baleful automatically rerolls all HP ups, extra life items, and defense-focused items. It's very easy to become unstoppably powerful as The Baleful, but you gotta be perfect. Needless to say, this Character should only be tried if you've gotten really comfortable with this game.

Throughout playing The Baleful you'll learn little tricks to exploit. Some of my favorites are using Blank Card with Holy Cards, exploiting the Perfection trinket (which you always get) with items like Ghost Pepper, or chasing libraries to find Book of Shadow or Book of the Dead. There's a lot to learn over your hundreds of deaths as this character, but feel free to look more tips up if you can't take it anymore.

The Harlot (T. Lilith)
???
Difficulty: Unknown
Secrets yet to be uncovered...

The Miser (T. Keeper)
???
Difficulty: Tricky
I respect Repentance for making The Keeper good after the pain of Afterbirth+. But what if we made The Keeper more like their AB+ self, but much more fun? The Miser starts with quad-shot instead of triple and one less HP with none of Keeper's starting items. Luckily, every enemy spills out money that quickly disappears if not picked up. This means you have a near infinite HP and money.

The big use for all that money is that almost every item you come across MUST be bought for either 15-30 cents. Shops you come across are heavily upgraded with much better items and more selections, but you'll also have to buy items from Treasure Rooms, Devil Deals, and so on this way. The Miser basically encourages that you hunt every coin dropped by enemies like a madman so that you can buy your way to victory. However, the biggest downside is that you have so little health. Only 2 hits and it can never be increase. So you may want to buy some defense items when you get the chance.

The Empty (T. Apollyon)
???
Difficulty: Unknown
Secrets yet to be uncovered...

The Fettered (T. Forgotten)
???
Difficulty: Unknown
Secrets yet to be uncovered...

The Zealot (T. Bethany)
???
Difficulty: Unknown
Secrets yet to be uncovered...

The Deserter (T. Jacob)
???
Difficulty: Unknown
Secrets yet to be uncovered...

Part 3: Rebirth Secrets (1/3)

Rebirth is the base form of the game with the 2nd most individual Secrets at 178. Luckily, I think Rebirth's Secrets are also the easiest of the bunch (outside of one Character's Completion Marks) and a very large chunk of them can be unlocked just by playing the game. Almost every Floor and Character unlock is counted as a Rebirth Secret so if you've been going in the order of this guide, you're already partway there!

The Harbingers
The horsemen are loose.
This one is simple enough. The Harbingers are 4 horseman boss fights (Famine, Pestilence, War, and Death) that are seen in Chapters I - IV (in that order) and are unlocked when you defeat Mom for the first time. They are not the only horsemen, but are the only Harbingers if that makes sense. Be sure to get good at these fights as they all show up in the Boss Rush and Mega Satan fight. The following Secrets also have to do with the Harbingers.

A Cube of Meat + Related Secrets
Unlocked a new item(s)
The Cube of Meat and Bandage Ball are two items that are ALWAYS found after killing a Harbinger and therefore are unlocked when you unlock The Harbingers (see above). The Secret says Cube of Meat, but sometimes the Cube of Meat will not spawn at all and be entirely replaced by the Bandage Ball.

There are two more Secrets related to these items, being Super Meat Boy and A Bandage. Super Meat Boy does not unlock an item while A Bandage does. Both of these require getting 4 of their respective items. There are many ways to do this such as using the Potato Peeler or using Lilith and her Box of Friends. The simplest way is to fight all the Harbingers as proper bosses (Gotta Meat Em All!); which luckily there's an easy way to do so right below this!

The Book of Revelations
Unlocked a new item.
This item grants a soul heart on use, but also guarantees your next will be one of the 4 Harbingers if the boss isn't already pre-determined. However, to unlock it you must kill one of the Harbingers. You will probably wind up doing this anyway, but I recommend trying to kill Famine or War first as they are easy fights. Death is the only Harbinger you really need to worry about.

Mom's Heart Endings
A whole bunch of 'em.
In Parts 1-2 I already showed how you can unlock It Lives!, Eden, and ??? with Mom's Heart. Out of the 11 times you have to defeat Mom's Heart, this makes up the 1st, 10th, and 11th times. Defeating it for the 2nd, 3rd, 4th, 6th, 7th, 8th, and 9th time all gives you specific Endings & Secrets. These Secrets are as follows: Rubber Cement, A Noose, Wire Coat Hanger, Ipecac, Experimental Treatment, A Quarter, and A Fetus in a Jar.

Mom's Heart is a tricky fight with 1 heart damage, enemy summons, and difficult bullet patterns. Be sure to kill enemies first as it will make the heart invulnerable. Any items that slow bullets or make you invulnerable can save you in the fight. You can also use the bible for a one-hit kill on Mom's Heart, much like with Mom herself (see below in the "A Halo" Secret).

Boss Rush Completion Marks
A whole bunch of 'em.
In Part 1 I explained the Boss Rush. For a reminder, beat Mom in under 20 minutes. You can press TAB while in Isaac to toggle a timer if you're having trouble keeping track. Every Character in the game must make it to the Boss Rush and complete it for a Completion Mark.

Do not let the early placement of the Boss Rush fool you, many of the endgame boss fight Secrets are easier to complete than the Boss Rush depending on the Character (Ex: I beat both Chapter VI's with The Lost wayyyyyy before the Boss Rush). This is because the Boss Rush is long, you don't have a lot of time to get really strong, and there isn't a real strategy outside of just getting good at almost every Chapter I - IV boss fight. Typically you should only try the Boss Rush if you've got a run that prioritizes high damage per second or if you have buff items such as the XI - Strength or III - Empress tarot cards. Active items are very helpful in the Boss Rush as bosses spawn in sets of two and give you two charges each time this happens; allowing for some real nonsense with items like Box of Friends.

Mr. Mega & A Small Rock
Unlocked new items.
I've already sort of talked about tinted rocks in Part 2, but now is the time to go in-depth. In Chapters I - III, there is a small chance that a rock (no urns, mushrooms, skulls, etc) will be slightly miscolored with an "X" on it. The further you go, the harder it is to spot them but they are there. Blowing up tinted rocks typically gives you either keys or soul hearts. After blowing up 10 you'll unlock Mr. Mega (often found in Treasure Rooms). Blow up 100 tinted rocks you'll be able to find A Small Rock in tinted rocks, which is straight damage up item for "free".

Monstro's Tooth
Unlocked a new item.
Possibly the easiest Secret in the game, you just have to make it through Chapter I and enter Caves I. That's literally it.

Lil' Chubby
Unlocked a new item.
Much like with Monstro's Tooth, you just have to clear Chapter II and enter Depths I. This is, of course, a little bit harder but the Caves are just as much of learning process as the Basement.

Loki's Horns
Unlocked a new item.
You may be familiar with the boss called Loki in Chapter 3. Well, there is a rare chance to get the posthumous version of him (much like other bosses) called Lokii in Chapter 4. Killing Lokii will unlock this item. The boss can effectively only show up on Womb I and basically acts as fighting two Loki's at the same time.

Reference Bosses
New bosses everywhere!
There are 4 alt versions of normal bosses that you can unlock for Chapters I - IV. The overlying theme is that these bosses are references to previous games of The Binding of Isaac: Rebirth's creator, Edmund McMillen. Upon killing any of these bosses, you get a Secret in the form of a guaranteed drop the first time they die. These Secrets are as follows:

• Something From The Future (Steven as an alt for Gemini) - Unlocked by beating Chapter I 40 times. Unlocks Little Steven once killed.
  
• Something Cute (C.H.A.D. as an alt for Chub) - Unlocked by beating Chapter II 30 times. Unlocks Little C.H.A.D. once killed.
  
• Something Sticky (Gish as an alt for Monstro II) - Unlocked by beating Chapter III 20 times. Unlocks Little Gish once killed.
  
• Something Sticky (Triachnid as an alt for Daddy Long Legs) - Unlocked by completing Chapter V: Cathedral 10 times. Unlocks nothing once killed : (

Isaac Completion Marks
A whole bunch of 'em.
As told in Part 1, you can reach two different Chapter V's after unlocking It Lives! One of such is The Cathedral (accessed by the glowing light), where you fight a holy version of Isaac. Defeating Isaac as each of the Characters will unlock a item for a Completion Mark.

Isaac is a weird fight because it gets easier the longer it goes. Isaac has three phases, he starts on the floor crying and with fire fast moving tears along with summoning enemies. Soon he will stand up and unleash occasional holy light along with constant streams of very difficult tear patterns. If you survive that, then Isaac will grow wings and teleport into the sky. Once he does that, holy light will begin fill the room. Move to the corners of the room opposite to where the holy light starts or you WILL be hit. Once that's over, he will teleport back down to do a close range tear attack or two before repeating the process. This last phase is more annoying than anything and it's mostly the 2nd phase you have to prepare for.

Part 3: Rebirth Secrets (2/3)

The Book of Sin
Unlocked a new item.
Throughout the game, you can run into these mini-bosses named after the 7 Deadly Sins. They can be found in random rooms as a separate encounter, in Greed Mode, in the Mega Satan fight, and Greed specifically can be found by hording too much money in Shops and Secret Rooms. Each sin has a super variant found randomly, but I believe you need to only kill the base versions for this Secret. The sins are simple fights compared to bosses with limited movesets and low HP so this Secret is not too difficult.

A Gamekid
Unlocked a new item.
Arcades are a frequent special room that costs a coin to enter and host various machines and beggars. Enter 10 of these and unlock the Gamekid.

A Halo
Unlocked a new item.
In reference to the Epilogue Ending, where Isaac's Mom dies to a Bible, using The Bible active item will instantly kill Mom, Mom's Heart, and It Lives! when used in the room. Doing this for the first time to any of them will unlock the Halo item.

The Scissors
Unlocked a new item.
The actual easiest Secret to unlock. Simply die 100 times. You probably already have this one huh?

The Parasite
Unlocked a new item.
To unlock this Secret, you must own 2 items pertaining to something "dead". For example, you can obtain Bob's Rotten Head, Dead Cat, Cricket's Head, or Tammy's Head. Bob's head is found in treasure rooms and sometimes for killing Sloth. Dead Cat is found in red chests and in Devil Deals. The last two are found in Treasure Rooms and rarely in gold chests.

Everything Is Terrible!!!
The game just got harder!
Those with keen eyes may have noticed I ignored the 5th defeat of Mom's Heart earlier. Well, doing so permanently makes the game harder is a lot of subtle ways. The most notable change is that champion enemies and curses (normally found in Hard Mode) are also a fair bit more common in normal mode and are even more frequent in Hard Mode.

Mom's Contact
Unlocked a new item.
This requires obtaining the "Yes Mother?" Transformation, which creates a knife behind you that damages enemies. Items in this Transformation are basically any items that starts with "Mom's". These items are typically Shop items or Boss Room items.

The Necronomicon
Unlocked a new item.
To unlock this Secret, you must use the XIII - Death tarot card 4 times. All tarot cards are found in chests, Shops, as room drops, and generated by some items and consumables. XIII - Death is not anymore or less common than the other tarot cards so getting an item like Deck of Cards can be very helpful for this Secret. Blank Card can allow you to reuse a XIII - Death card multiple times so that's something to keep in mind.

Satan Completion Marks
A whole bunch of 'em.
As told in Part 1, you can reach two different Chapter V's after unlocking It Lives! Earlier, I went over The Cathedral and it's items. The other chapter is Sheol (accessed by the trapdoor), where you fight Satan at the end. Every Character must defeat Satan for a Completion Mark. Satan is a 3-phase fight that goes as such:

1. The Fallen along with two explosive leeches. If you can beat The Fallen or Krampus, you can beat this phase.
   
   
2. Satan themselves with stand up and begin to fire upon you. Standing to either side will cause them to fire a series of fast bullet patterns that can be tricky to dodge. Going into the middle will have Satan fire a large brimstone laser like The Dark One. The strategy is to rotate between sides to force Satan to constantly change their attacks and waste lasers to hit you.
   
   
3. Satan will stand up and begin to stomp on you with goat legs just like Mom's foot. There are two stomps at a time and sometimes an explosive leech will spawn. Always keep moving to avoid the legs and only stop if both are on the ground. Satan can step on the leeches for massive damage so exploit this the best you can.

The Lamb Completion Marks
A whole bunch of 'em.
As said in Part 1, you can reach the "final" Chapter known as Chapter VI. Just like Chapter V, there are two different Chapter VI's, but there is no way to accidentally enter the other one or end your run as long as you grab The Polaroid or The Negative for The Chest and Dark Room respectively. The only boss of Chapter VI: Dark Room is The Lamb. Every Character must defeat The Lamb for a Completion Mark.

The Lamb is a tricky fight due to its wide variety of attacks. It will slowly float towards you and unleash a variety of bullet attacks. After enough damage, The Lamb's head will separate from it's body and become two different things to kill. The body occasionally fires explosive shots and spawns flies while the head is the big issue. The head will spit a flurry of homing bullets, fire, and brimstone laser attacks that can overwhelm you. The Lamb doesn't have too much HP so this fight is mostly of dodging and quick thinking.

??? Completion Marks
A whole bunch of 'em.
As said in Part 1, you can reach the "final" Chapter known as Chapter VI. Just like Chapter V, there are two different Chapter VI's, but there is no way to accidentally enter the other one or end your run as long as you grab The Polaroid or The Negative for The Chest and Dark Room respectively. The only boss of Chapter VI: The Chest is ???. Every Character must defeat ??? for a Completion Mark.

??? is similar to Isaac's fight but different in a few ways. Most notably, ??? loses the holy light attacks and instead spawns a large quantity of flies and much more difficult homing bullet attacks. You do not need to run around the room like in Isaac's fight, but never get too close to ??? and make sure any flies it spawns are dealt with swiftly.

Dad's Key
Unlocked a new item.
In Part 1, I detailed how the Angel fights work and how to access Mega Satan. If you ever collect both Key Pieces, you will unlock this item.

Donation Machine Secrets
A whole bunch of 'em.
The Donation Machine is a machine found sometimes in Shops and elsewhere that allows you to deposit coins into a counter that saves between runs. When depositing coins, both your Angel Room chance and luck can go up the more coins you put in. There is a small chance that putting in a coin will break the machine for the rest of the run, meaning that you will have to fill the Donation Machine over many, many runs. Avoid bombing the Donation Machine as it will remove coins from it. There are Secrets for reaching various milestone in the Donation Machine as follows:

• Blue Map - 10 coins will unlock this item.
  
• Store Upgrade Lv. 1 - 20 coins will increase the amount of items that is available in Shops.
  
• There's Options - 50 coins will unlock this item.
  
• Store Upgrade Lv. 2 - 100 coins will increase the amount of items that is available in Shops.
  
• Black Candle - 150 coins will unlock this item.
  
• Store Upgrade Lv. 3 - 200 coins will increase the amount of items that is available in Shops.
  
• Red Candle - 400 coins will unlock this item.
  
• Store Upgrade Lv. 4 - 600 coins will increase the amount of items that is available in Shops.
  
• Blue Candle - 900 coins will unlock this item.
  
• Stop Watch - 999 coins will unlock this item.

Lucky Toe
Unlocked a new item.
Fun Fact: You can blow up the Shopkeepers seen in Shops and Secret Rooms. Doing so can spawn spiders, coins, or nothing as well as raising your Devil Deal chance. Blowing up 20 Shopkeepers will unlock this Secret.

Part 3: Rebirth Secrets (3/3)

Counterfeit Coin
Unlocked a new item.
In arcades, Greed Mode, and sometimes at random you can find a Shell Game that looks like a beggar above 3 skulls. Here you can play a version of the Shell Game in exchange for a coin that doesn't actually care what skull you pick. Play this game 100 times to unlock this Secret.

Guppy's Hairball
Unlocked a new item.
To unlock this, you must gain the "Guppy" Transformation. This is done by picking up 3 "Guppy's" items (Dead Cat is also included). Guppy items are very regularly found in red chests and Devil Deals, but can be spotted elsewhere occasionally. It's generally good to get the "Guppy" Transformation when you can as it allows you to spawn friendly flies for every single time you deal damage (this is VERY powerful).

A Forgotten Horseman
Unlocked a new boss!
This is one of the two bosses that makes me specify Harbinger from horseman. Conquest is a horseman that can be found in Chapter IV, but must be unlocked by taking 10 Angel Room items. Conquest is actually easier than Death, only being trouble through homing shots and holy beams, and only drops White Pony upon being killed.

Lucky Rock
Destroy 100 rocks.
This is one of the few items whose subtext literally just tells you what to do. I'm not even needed for this one!

Rebirth Alternate Floors
It's about damn time I used this keyword!
The Binding of Isaac: Rebirth has an unlockable Alternate Floor for Chapters I - III. Each of them require you to beat all of the bosses of their respective Floors, but not necessarily IN them. This means that both the Boss Rush and Greed Mode are very helpful for accomplishing these. For some reason, you do not have to beat the bosses added in Repentance such as Baby Plum, Bumbino, or Reap Creep.

Chapter I receives the Cellar, Chapter II has the Catacombs, and Chapter III gets Necropolis. Each of these Alternate Floors has new enemies, room layouts, and bosses.

Krampus & Head of Krampus
Unlocked a new mini-boss and item.
Upon taking 20 Devil Deal items, you can unlock a mini-boss that will show up in Devil Rooms like Greed in Shops. The fight works a lot like The Fallen, but Krampus does not split in half and can rotate his brimstone lasers as well as shoot them diagonally. Once you kill Krampus, you unlock Head of Krampus and can either get that or the Lump of Coal as a boss reward.

Butter Bean
Unlocked a new item.
To unlock this, destroy 100 poop. Poop is very common in Chapter I, spawned a lot by Larry Jr., and can be spawned infinitely by ??? (Blue Baby).

Little Baggy
Unlocked a new item.
To unlock the Little Baggy, you must get pretty close to the "Spun" Transformation. This Transformation requires you to have 3 "needle" items while unlocking Little Baggy only requires 2. Some examples of "needle" items are Roid Rage, The Virus, Growth Hormones, Speed Ball, and Experimental Treatment.

Blood Bag
Unlocked a new item.
Blood Donation Machines are machines that deal a half heart of damage (full heart in later Chapters as per usual) and will spit out a varying amount of money until it explodes from overuse. These machines prioritize red health even when you have soul hearts so be careful. Using this machine 30 times will unlock the Blood Bag, an HP up item than can be found in overused Blood Donation Machines. Making yourself invulnerable through different effect allows for free uses of this machine.

The D4
Unlocked a new item.
Unlocking the D4 is pretty straightforward and just takes some time. You have to find arcades which can be found in Chapter I - IV, require 1 cent to enter, and contain a variety of machines. Blow up 30 machines within the arcade rooms and you will unlock the D4.

Mom's Heart Hard Mode Secrets
Unlocked... some babies?
This is part 1/2 where Hard Mode matters for Completion Marks. Defeating Mom's Heart or It Lives! with any Character on Hard Mode grants a baby for the specific Character. These babies can be used in the now somewhat defunct older co-op mode of The Binding of Isaac: Rebirth which is activated by a second controller input. For most, these babies are useless and serve as Secret fodder. Also Apollyon, for whatever reason, unlocks the Smelter item instead of a baby for this Completion Mark?

Lord of the Flies
You became the Lord of the Flies.
"Beelzebub" is a Transformation you obtain by collecting 3 of the many fly items that are found mostly in Treasure Rooms but not always. This Transformation grants flight and turns all enemy flies into friendly flies.

Part 4: Afterbirth Secrets (1/2)

Afterbirth is the first expansion of the game and adds the smallest amount of Secrets at 98 new Secrets. The most notable additions of Afterbirth in terms of Secrets are 10 new unlockable Challenges, more Hard Mode Completion Marks, and Greed Mode. However, due to the Greed Donation Machine and the aforementioned Hard Mode Completion Marks, Afterbirth can wind up being a very grindy process to fully complete.

Hush Completion Marks
A whole bunch of 'em.
The Blue Womb is an optional floor after Chapter IV that I detail the unlocking of in Part 1. Upon entering this floor, you start in a prep room with some gold chests, two Treasure Rooms (2 items to choose between in each), and a Shop. You'll need these because at the North of the prep room is a large gate that opens when you get close. Enter it and you will face the super hard challenge boss called Hush. Every Character must defeat Hush for a Completion Mark.

Hush's fight is very hard to simplify since Hush has a ridiculous health pool and the fight can easily go on for over 5 minutes. The fight starts with fighting a weakened version of ??? that is dealt with pretty quickly if you have solid damage. See The Chest Secrets for tips on ???. After that, Hush will rise from the floor and you'll notice two things. One, Hush is massive and is almost impossible to miss. Two, Hush is the resident "bullet hell" fight and expects you to maintain damage while bullets fill the screen.

Hush will swap to a variety of different bullet hell attacks as the fight progresses. Sometime it will even go underground and summon enemies, Hush itself being invulnerable during this time. Hush's most notorious attack is the Continuum shots. Hush will fire tears off-screen, seemingly missing you completely. These tears will come back around from the opposite side of the screen in fast but predicable patters. My strategy is to stand still where the bullets are not flowing through on the first pass and move very deliberately to another said location if Hush launches another attack.

Hush is one of the few bosses to have what is called a Boss Armor. This makes it so you can only deal a certain amount of damage to Hush in a short period of time. This means you cannot one-shot your way through Hush and must learn its attacks in order to succeed. My tips are to only attempt Hush on high HP and to bring any bullet stopping items you have such as Infamy, Stopwatch, or the I'm Drowsy Pill. Neither of these trivialize the fight, but will raise your odds of beating it significantly.

Greed Mode Completion Marks
A whole bunch of 'em.
In Greed Mode, there are three sets of unlocks that can be obtained. One for beating Greed Mode's final boss: Ultra Greed. The other two I will cover later down the guide. Ultra Greed is on his own Floor after the Shop Floor and is preceded by a mini-boss room. Every Character must defeat Ultra Greed for a Completion Mark.

Much like Hush's fight discussed above, Ultra Greed's fight is difficult to explain and also has that pesky Boss Armor. Ultra Greed will patrol around his arena, spinning and spitting a variety of coin tears at you. Sometimes he will stomp on the ground to summon keeper heads other enemies. Ultra Greed makes you drop coins when hit, like the other Greeds, and heals from any coins in picks up so be sure to pick up any lose change.

Ultra Greed's main attack outside of spitting coins and summoning enemies is the slot machine. Occasionally, Ultra Greed will stop and spin his coin eyes. Depending on what they show up as, it will do one of 4 things:

1. Both Eyes Are Bombs - Ultra Greed will fill the room with destroyable bomb coins that will blow up after a few seconds. Ultra Greed blocks during this, receiving extremely reduced damage.
   
   
2. Both Eyes Are Hearts - Ultra Greed will fill the room with with destroyable heart coins that will heal Ultra Greed after a few seconds. Ultra Greed acts as normal while this happens.
   
   
3. Both Eyes Are Keys - Ultra Greed will fill the room with destroyable key coins that will turn into golden keys. These will unlock the various golden doors around the arena, each door unleashing a swarm of low health Greed Gapers. Ultra Greed blocks during this like with the bomb coins.
   
   
4. Eyes Are Different Things - Ultra Greed will drop a few spinning coins and then act as normal. These coins are destroyable, last for a long time, and deal contact damage.

Ultra Greed will become more red and angry as he takes damage. The angrier he is, the more coins and enemies he will spawn and the faster he becomes. Ultra Greed tests your ability to crowd control due to the large amount of stuff he spawns. Not destroying his summons or coin drops can make the fight very difficult for you. Also, generally avoid standing near Ultra Greed as he may walk into you on accident or spit on you for near unavoidable damage.

Mega Satan Completion Marks & MEGA
More babies?!
In Part 1, I went over how to get the Key Pieces needed to unlock the door to Mega Satan in Chapter VI. Once going in, you will get to a platform with a pentagram. Standing on this will begin the Mega Satan fight. While Mega Satan was added in Rebirth, in Afterbirth every Character must defeat Mega Satan for a Completion Mark. These Secrets, like with Mom's Heart on Hard Mode, unlock babies for the old co-op mode of The Binding of Isaac. Also, if you beat Mega Satan with every Character then you will unlock the MEGA Secret which grants you a powerful active item.

Mega Satan is a marathon of a fight, requiring you to take on difficult attacks and many other bosses. Mega Satan does not have a health bar but does have Boss Armor so you just need to wail on him. During this, Mega Satan will use their hands and face to perform many shockwave and bullet attacks. Mega Satan may also send in sins to fight you if you're taking too long to reach his phases. Speaking of, Mega Satan has 4 phases that start after you lower this initial part enough:

1. Mega Satan will stop fighting and summon in Famine and Pestilence. Beat these and you will then fight War and Death. After all 4 Harbingers are beaten, Mega Satan will resume fighting. Conquest and the Headless Horseman apparently skipped work today.
   
   
2. Mega Satan will, again, stop fighting and summon Super Envy. Beat it and you will then fight Super Wrath and Super Lust. Beat them and finally you'll fight Super Greed, Pride, Gluttony, and Sloth. After all super sins are dead, Mega Satan will resume fighting.
   
   
3. Mega Satan will... once again... stop fighting and summon a fallen version of Uriel. This fight is identical to Uriel, just miscolored. Kill Uriel and you'll then fight fallen Gabriel. Kill both angels and Mega Satan will resume fighting.
   
   
4. After enough damage, Mega Satan will sink down, seemingly killed. They will then rise as a skeletal version of themselves and unleash a difficult set of bullet and fire attacks akin to The Lamb. This phase does not have much health, and beating it will kill Mega Satan for real this time.

First and foremost, Mega Satan's hands can be killed, but they will come back after some time. A lot of pre-skeletal Mega Satan's hardest attacks are because of his hands' shockwaves. Listen for a deep growl because that means the head is going to unleash a huge brimstone laser down the middle of the screen. The bosses Mega Satan summons aren't the hardest, but not being decent at fighting them will make this fight very hard. Try the Backasswards Challenge (see Part 7) if you want easy access to practice this fight. Once you kill Mega Satan, you will get an Ending or possible a Void Portal.

Part 4: Afterbirth Secrets (2/2)

Greed Donation Machine Secrets
A whole bunch of 'em.
After beating Greed or Greedier Mode and their respective bosses, a Donation Machine will fall from the ceiling titled "Greed". You put leftover coins from your run in here with a chance for the machine to break. Like the Donation Machine, different milestones will unlock various items. I've already shown some of these Secrets during Part 2, so I will be skipping those ones:

• Lucky Pennies - 1 coin will unlock these items.
  
• Special Hanging Shopkeepers - 10 coins will unlock this object.
  
• Wooden Nickle - 30 coins will unlock this item.
  
• Everything Is Terrible 2!!! - 111 coins will unlock this Secret.
  
• Special Shopkeepers - 234 coins will unlock this object.
  
• Greedier! - 500 coins will unlock this Secret.
  
• Store Key - 666 coins will unlock this item.
  
• Generosity - 999 coins will unlock this Secret.

Blinding Baby
Another baby...
To unlock yet another co-op baby, you must first clear Chapter V: Cathedral as Eden (see Part 3). Afterwards, you'll be able to find the Blank Card in Shops, Treasure Rooms, and Secret Rooms. This active item allows you to mimic your currently held card without consuming it. Locate a XIX - The Sun tarot card and use Blank Card to copy its effect to unlock this very well hidden baby.

Hard Mode Completion Marks
Even more babies?!?
This is where me telling you to play on Hard Mode at all times comes into play. Afterbirth adds a fun little mechanic where beating all, and yes I mean all, Completion Marks on Hard Mode gives its own unique set of Secrets in the form of more co-op babies! As someone who did not play on Hard Mode for most of the game, going back and getting all Completion Marks effectively two times is brutal and I would avoid it at all costs. Also, getting The Lost's version of this Secret unlocks Godhead as an item instead of a baby for some reason.

Part 5: Afterbirth+ Secrets (1/3)

Afterbirth+ is the 2nd expansion to Rebirth and has had a weird history in terms of Secrets. It used to only have 63 Secrets and a bunch of pre-unlocked items that really should've been behind Secrets (including a Character). Then, Afterbirth+ got some mini "Booster Pack" updates that created many new Secrets.

This now sets Afterbirth+ at 127 Secrets and makes it, in my opinion, the hardest of the Secret sets to unlock. This is because of some brutal boss fights, some really oddball Secrets, a particularly punishing Challenge, and the dreaded horrors of the Daily Challenge Secrets. Prepare yourself...

Delirium Completion Marks
A whole bunch of 'em.
One of the last steps along the unlocking of Floors in is the "New Area" Secret. I went over the steps of all that and how Void Portals work in Part 1. Upon entering the Void, you will explore a massive floor consisting of room layouts from all previous Chapters. There are many Boss Rooms, all with bosses from previous Chapters and Boss Room rewards for killing them. One Boss Room will randomly host Delirium. Beat it and you get an Ending. All Characters must beat Delirium for a Completion Mark (indicated by the Completion Mark page being torn/bloodied).

Delirium is a nightmare fight that has been criticized for being too random to be considered fair. Delirium will perpetually fire a large amount of slow moving bullets no matter where it teleports to. Sometimes these bullets are explosive or faster, but not commonly. Delirium will also randomly transform into any boss you've killed on your run thus far. You do not need to kill the boss as Delirium's HP is shared, but it will be able to use any of that boss' attacks. There are very few things that Delirium cannot turn into (such as the 2nd phase of Hush). As Delirium takes damage, it will begin to, much like Ultra Greed, transform and teleport faster to the point where it is difficult to keep track of it. Enemies summoned by Delirium's forms will remain regardless of what form Delirium takes.

There's not really a lot to say about strategies in regards to Delirium because of how wild the fight is. Delirium is another member of the Boss Armor club mentioned in Hush's fight. It is also immune to most insta-kill attacks such as the Chaos Card. Your best chance with Delirium is to takes items that make you largely invulnerable and that slow bullets... just like with Hush. The issue is that Delirium's forms can cause hits that feels almost unavoidable such as a boss off-screen using Brimstone. The worst of it comes from when Delirium's teleports can rarely have it spawn on top of you. Don't beat yourself up if your run ends at Delirium, this fight is just a bit ♥♥♥♥♥♥♥♥.

Greedier Mode Completion Marks
A whole bunch of 'em.
Greedier Mode is unlocked within Greed Mode using the Greed Donation Machine. This mode is effectively the Hard Mode of Greed Mode, having the traditional Hard Mode changes along with less money per wave and more waves. Get to the end and you will fight Ultra Greedier, a similar but ultimately very different boss to Ultra Greed. All Characters must defeat Ultra Greedier for a Secret. Defeating Ultra Greedier will also count as a kill on Ultra Greed for the purposes of Completion Marks.

Ultra Greedier starts out like Ultra Greed, but his rage mechanic grows faster has more health during 1st phase. Once the phase is over, the golden statue of Ultra Greedier will come to life and begin to attack. Ultra Greedier summons bomb coins, causes shockwaves and explosions with his fists/jumps, shoots explosive coins with his mouth, and unleashes gold brimstone lasers from the various boss doors.

Generally you want to keep a distance from the Ultra Greedier and especially keep to corners to avoid the golden lasers. Any items that negate full heart damage, shockwaves, or explosion damage are godsends in this fight and should be prioritized in shops. Ultra Greedier does not have very much health so bursting down this boss in short stretches of making yourself vulnerable is the best way I've found to go about it.

Once More With Feeling, Butter, and RERUN
Unlocked new items and a strange power.
These Secrets mark the beginning of those oddball Secrets I mentioned at the beginning of this section. Afterbirth+ added the ability to take a Victory Lap after any run where you clear Chapter VI: Dark Room. This allows you to redo your entire run with the same Floor layouts and bosses, but you keep all of the items, pickups, and health you had from your previous run. This will obviously trivialize the Victory Lap run, but if you clear Chapter VI: Dark Room again it does grant you a new pill type. Do note that outside of these Secrets, all other Secrets are unobtainable in Victory Laps.

Where this gets messier is with the other Secrets. All you need to do for Butter! is what you did for the previous Secret, but again for your 2nd Victory Lap clear. The 3RD Victory Lap run is where you get RERUN, and that 3rd Victory Lap removes all Shops and forces you into playing as The Lost. Hopefully after 3 runs worth of items and stat increases you should be able to bulldoze all foes you come across, but dying here means a whole lot of wasted time so be careful! Once The Lamb is dead for the 4th time, you unlock the ability to start a RERUN. This is a slightly modified Victory Lap option that is available anytime you complete a run and then attempt to continue it in the main menu.

Hat trick and 5 Nights at Mom's
Unlocked a new item and some special rocks.
This Secret requires that you get a 3-win streak. On the Character Select menu, you can see a tracker that lists your current number of runs that did not result in death in a row. Getting 3 wins in a game as punishing as Isaac in a row can be quite hard. Some tips I suggest are to play a Character you're good with, avoid optional difficulties like Hard Mode or extra bosses, and go for the earliest victory you can. This can be Mom's Heart or either Chapter V depending on how far you've progressed in the game. Doing any Floor further than that is an unnecessary risk. 5 Nights at Mom's is exactly the same as Hat trick!, but you need to get a 5-win streak instead.

Sin Collector
Unlocked a new item.
This Secret requires that you have the entire Bestiary complete. In the Stats section of the main menu, you can locate your Bestiary and track every enemy you've killed. I'll be entirely blunt here, the Bestiary is bugged and does not work properly in Isaac. It's best to work on other Secrets and let the game decide when you've earned this Secret.

ZIP!
Unlocked a new item.
Unlocking ZIP! is a tough one. You need to make it all the way to and clear Chapter VI: Dark Room in under 20 minutes. First step, you MUST pick a Character that start with unrestricted flight (Azazel or The Lost). You'll be too slow on the early Floors otherwise. You need to make a straight line for the Boss Room on every Floor, skipping Shops and Treasure Rooms if you must. Picking up any consumables or items that grant full floor vision such as XXI - The World, Ansuz, or The Mind are almost essential, and avoid playing on Hard Mode so some curses can cost you the run. Using items such as We Need To Go Deeper or Ehwaz can allow you to skip entire floors using easy trapdoors, but losing out on items and health can be risky so do this with caution. Also, for the love of god do NOT forget The Negative.

Part 5: Afterbirth+ Secrets (2/3)

It's the Key
Unlocked a new item.
Unlike ZIP!, this Secret is a test of patience and awareness. You need to clear Chapter VI: Dark Room without having picked up a heart, coin, or bomb. The heart part is "easy", just play as The Lost as you can't have hearts anyway. The hard part is going the entire run while avoiding the instinct to pick up coins and bombs. Neither pickup is ever mandatory to beating a run, just take it slow and pay attention to your movements in rooms. Avoid items like Pageant Boy or Bomb Bag that can spawn pickups directly in your path. Also, familiars and enemies that collect pickups WILL cause you to fail this Secret so be careful.

Mr. Resetter!
Unlocked a new item.
Up there with some of the easiest Secrets in the game. To reset a run, you simply need to hold down the R key and a new run will automatically begin. Do this 7 times in a row and ta-da!

Sprinkler, Telekinesis, Leprosy, Pop!, and Living on the edge
You're untouchable!
To unlock the first 4 Secrets you have to, in order, clear Chapters I, II, III, and IV without taking damage. The easiest way to do this is just to play as The Lost. The Lost cannot take damage anyway, so if you win a run with The Lost you'll have all of these automatically unlocked. The only issue is playing The Lost (protip: unlock the Holy Mantle upgrade in Greed Mode). Living on edge will also be obtained doing this as you have to complete a Chapter with only half a heart (or less) left.

U Broke It!
Unlocked a new item.
To unlock this Secret, you need to have 50 items in one run. The idea behind this is to cause a game break, but I do NOT have the time or will to explain the various tricks behind Isaac game breaking in this guide. Instead, this is still possible to get in a vanilla context. Some Characters start with more items than others and have the ability to gain even more (such as Lilith) so prioritize playing as them. Having a very long run where you stop by every optional area can net you a large amount of items if you take Shops into account. Though, the best way in my opinion is to become filthy rich in Greed Mode as it allows you to buy infinite items if you have the cash.

AB+ Alternate Floors
Alt stage to the everything.
There are the Alternate Floors known as Burning Basement, Flooded Caves, Dank Depths, and Scarred Womb. To unlock these, you need to defeat Mom's Heart (see Part 3) 11, 16, 21, and 30 times respectively.

Something wicked this way comes (twice)
Unlocked (even more) new bosses.
You can unlock a rogue's gallery of new bosses for Chapters I - IV by clearing Chapter VI: Chest 3 and then 6 times (see Part 3).

The gate is open and Black Hole
Unlocked a new enemy and an item.
Once you clear Chapter VI: Dark Room for the first time, you will find new enemies in the shape of portals that act as spawners for other enemies. These portals appear only in The Void. You'll need to make quite a few trips to kill 20 of them to unlock Black Hole.

Note: There is a similar portal enemy in Chapter III: Masoleum that MAY count towards this Secret but I am not sure myself.

Fast Bombs
Unlocked a new item.
One of the bosses unlocked in the first iteration of Something wicked this way comes is a Chapter I boss called Little Horn who loves bombs. He's not particularly difficult and shows up often, so kill this little guy 20 times and this Secret is yours.

Wooden Cross and Blanket
Unlocked new items.
Occasionally on Floors you'll find rooms locked behind wooden planks that require 2 bombs to open. This is Isaac's bedroom, and inside you can find a bed that will fully heal your red hearts once if you touch it. Doing this once and then 10 times is the key behind these Secrets. There is also always a bed available in Home (see Part 1).

Huge Growth, Lachryphagy, and Marbles
Unlocked new items.
These Secrets are not actually related, but they coincidentally all have the same solution. The first step is to find a Shop/Secret Room active item called Placebo. While Placebo is not always guaranteed to show up, checking every Shop and using restock machines can make it somewhat consistent. Placebo mimics your current held pill without consuming the pill, allowing you to repeat pill effects easily:

• For Huge Growth, you'll want to find the One Makes You Larger pill and Placebo it 5 times to grow massive. Some items such as Magic Mushroom, XI - Strength, or will also count towards this total.
  
• For Lachryphagy, you need to have obtained 10 items or effects that grant you Tears Up. While this is obtainable with focusing stat up items, Placebo and a Tears Up pill is your best bet for consistently accomplishing this.
  
• To unlock Marbles, you'll first want to unlock the Gulp! pill with the Once More with Feeling Secret from earlier in this section. Gulp! will destroy your currently held trinket and add it to your passive items, allowing for more trinkets to be held. Using Gulp! and Placebo to swallow 5 trinkets in a single run will gain you this Secret.

Moving Box
Unlocked a new item.
This Secret involves 2 steps. First, you have to unlock the item Pandora's Box by clearing Chapter VI: Dark Room as Lazarus. This item is a one-time use active item frequently found in Shops. Bring this item all of the way to Chapter VI: Dark Room again, and use it there to unlock the Moving Box.

Jumper Cables and Extension Cord
Unlocked new items.
Extension Cord is a rather annoying and specific item to unlock. You need to have the following items on you at the same time: The Battery, 9 Volt, and Car Battery. These are all Shop items so Greed Mode or having items like Restock as well as plenty of cash it the way to go. You can find a new type of beggar called the Battery Bum specializes in giving battery items if given enough coins. Jumper Cables requires you to have any 2 battery-related items. Therefore, unlocking Extension Cord will also unlock Jumper Cables with it.

Lil Spewer
Unlocked a new item.
To unlock this Secret you need to die! In a very specific way to be specific. Using the item Ipecac or Bob's Rotten Brain (both usually in Treasure Rooms), you need to die to your own explosion. You can also do this with the Horf! pill, but the unlock for that it tied to Daily Challenges. You and I both don't want that...

Baby-Bender
Unlocked a new item.
This one's an easy one. While under the effect of anything that grants you homing tears (Spoon Bender, I - The Magician, etc), use I - The Magician or the Telepathy for Dummies active item. Tarot cards are pretty easy to come by in a run, so if you ever get purple tears then start hunting for the right one.

Part 5: Afterbirth+ Secret (3/3)

AB+ Checklist Secrets
A whole bunch of 'em.
I'm breaking the order of unlocks again because Afterbirth+ added a ton of Secrets due to the Booster Pack updates. These Secrets are unlocked just by doing a ton of simple tasks. I don't have advice for some of these unlocks that hasn't already been explained earlier or isn't self-explanatory, so we're gonna lighting round those ones:

• Mystery Gift - Destroy 500 rocks.
  
• Angry Fly - Gain the "Beelzebub" Transformation (see Part 3).
  
• Bozo - Destroy 5 rainbow poops. These aren't hidden/locked, just rare.
  
• Buddy in a Box - Have 5 familiars in a single run. Most items that are a buddy that follows you around is a familiar.
  
• Hairpin - Recharge using 20 Lil' Battery pickups.
  
• Ancient Recall - Use cards or runes 20 times.
  
• Era Walk - Obtain the Broken Watch and Stop Watch (doesn't have to be in the same run, see Part 3).
  
• Coupon - Purchase items from Shops or Devil Deals 50 times.
  
• Technology Zero - Pick up 2 of the "tech" items in the same run.
  
• Filigree Feather - Acquire both Key Pieces (see Part 1).
  
• Mr. ME! - Open 20 locked chests.
  
• 7 Seals - Defeat all of the Harbingers and Conquest (see Part 3).
  
• Angelic Prism - Defeat an Angel 10 times (see Part 1).
  
• Door Stop - Blow up a door or Secret Room wall 50 times.
  
• Death's List - Take 25 items from Devil Deals.
  
• Haemolacria - Acquire the item Blood Clot 10 times (usually found after killing bosses).
  
• Schoolbag - Enter 6 different Shops in one run.
  
• Trisagion - Take 25 items from Angel Rooms.
  
• Flat Stone - Acquire the item Rubber Cement 5 times (see Part 3).
  
• Sacrificial Alter - Take 50 items from Devil Deals.
  
• Mystery Egg - Have 3 charmed enemies in the same room.
  
• Rotten Penny - Have 20 friendly flies at any time (basically just gain the "Guppy" Transformation as shown in Part 3).

And now it is time for...
THE DAILY CHALLENGE SECRETS!

Daily Challenges are a run that is randomly pre-made with preset Characters, items, and end goals. Win or lose you only get one shot at a Daily Challenge, but can do practice runs to test the waters if you'd like. After the run is complete, you get scored on a leaderboard with everyone else who played today. To enable Daily Challenges, you must be connected online and have no mods enabled.

If I'm being entirely honest, there's nothing WRONG with Daily Challenges, but the Secrets tied to them are tedious for someone (such as myself) that does not care for score-chasing or leaderboards. I will now list all Secrets tied to this system in order of annoyance.

Broken Modem
Unlocked a new item.
To get this Secret, you must win 7 Daily Challenges. You do not have to win these runs in a row, but it does force you to perform well as you cannot restart the run and must wait until tomorrow if you die. Daily Challenges are almost entirely random, so I have no specific advice for you here (or the following Secrets).

Dedication
Unlocked a new item.
This stupid Secret forces you to play 31 DAILY CHALLENGES. You do not have to do these in a row or even have to succeed. You could (and maybe should) die in the first room with enemies. Regardless, we now know it's impossible to fully complete Isaac in anything less than 31 days...

The Marathon
Unlocked a new item.
Hate to say it, but the Marathon is the one I've been dreading here. This Secret took me weeks of pain. You must win 5 Daily Challenges in a row. While these do not need to be exactly 5 days in a row, the random nature of these runs can really screw you if you draw bad end goals, Characters, and/or Floor layouts. I unfortunately have no advice beyond getting really good at all of the Characters and playing super carefully. Your end time can go take a hike as far as I'm concerned.

Part 6: Repentance Secrets (1/2)

At last we arrive at Repentance. Released in 2021, Repentance is intended to be the final hurrah of The Binding of Isaac: Rebirth. This expansion both included a ton of brand new content and Characters as well as a full remaster of a popular fan-made expansion called Antibirth. This all culminates in one last, true ending for Isaac's story and a whole bunch of stuff for you to unlock.

Repentance sits as the king of the Secrets arms race standing at a STAGGERING 233 Secrets. If you've seen Part 2.5 then the reason why this is should be painfully obvious. We also have 2 new Completion Marks for all Characters to complete, 10 new Challenges, and a few odds and ends. Repentance includes some of the hardest bosses and new areas in the game, so while it's no Afterbirth+ this won't be a breeze either.

The Planetarium
Kids shouldn't believe in fortunes...
To unlock both the Planetarium (see Prologue) and the Telescope Lens trinket, you'll need to have collected 3 tarot and/or zodiac themed items. A lot of items can count towards this, but the easiest ones are the Magic 8 Ball (found after bosses), the Deck of Cards and Tarot Cloth (found in Shops), and the various zodiac symbols (like cancer, leo, taurus, etc) as well as Crystal Ball found in Treasure Rooms. Basically, it's a combination of going to every Shop/Treasure Room and getting a little lucky.

Forgotten Lullaby
Get that song out of her head.
After reaching Chapter III: Mausoleum (see Part 1), one of the possible bosses on Mausoleum I is the Siren. After killing her, she'll dissolve until only a skull remains on the ground. Use a bomb to blow up her skull and you'll find and unlock a trinket called the Forgotten Lullaby.

Fruity Plum and Plum Flute
Make a new enemy or friend!
A boss you can find in Chapter I is Baby Plum. If you kill her 10 times, you'll unlock the Fruity Plum. What's funny is that you can also defeat Baby Plum by doing nothing. If you don't attack her for 30 seconds; she'll leave you alone and fly away and leave the Plum Flute behind.

Repentance Alternate Floors
Even more alt stages?
As explained in Part 1, you can enter a different set of Chapters I - III. These Alternate Floors are more difficult than your usual Floors and, consequently, also have much stronger bosses. The Downpour and Mines have 4 unique bosses while Mausoleum only has 2 (which take up Mausoleum I as Mausoleum II is the fight with Mom).

If you defeat all of the bosses of a given Floor then you'll unlock the Alternate Floor to your Alternate Floor. Silly wording aside, the Downpour can now sometimes become Dross, the Mines can become Ash Pit, and the Mausoleum can become Gehenna. These also have their own unique enemies and bosses that are even harder.

Red Key
The other side is calling...
As detailed towards the end of Part 1, opening Mom's chest while at Home for the very first time will contain the Red Key and will also unlock it as an item to find in later runs.

It's now at this point that I'd like to direct you to Part 2.5 if you've not yet discovered what all of that is about. A LARGE amount of Repentance's Secrets comes from that.

Corpse Completion Marks
A whole bunch of 'em.
After making it to the end of Chapter III: Mausoleum and performing the steps mentioned in Part 1, you'll be able to use the knife to enter the Corpse. I would take your time here as the Corpse is not exceptionally difficult and you'll want to be prepared as possible for the fight ahead. At the end of Corpse II there will be an ominous hole in the ground leading to one of the hardest boss fights in the whole game. Simply known as Mother (formerly The Witness), this... thing must be defeated by every single Character for Completion Marks.

As said earlier, Mother is an incredibly tough boss fight. While she does not have as much health as Hush, she does have Boss Armor and has two phases both with very difficult attacks to maneuver around. Her first phase is similar to Mega Satan, being a large target at the top of the screen. Most of her attacks involved slamming, shooting, or throwing knives that create winding bullet patterns that are tough to dodge. You can almost entirely avoid the knife attacks by hugging the center of the back wall, but the rest you're on your own for. Her deadliest attacks are when she retreats to summon minions or when she plays... tennis?

When she summons minions, you need to kill them as fast as possible. Every one that's kept alive can hit you, but also will be turned into projectiles that can overwhelm you if too many get by. As for the tennis, she will grab a fistula and bounce it off of the back wall at increasing speeds. Not only can the fistula hit you, but every bounce creates waves of shots. This one in particular is incredibly hard to take no damage from and I usually just hope I get through the first phase before she uses it. Speaking of, once you do enough damage she will retreat and unleash a massive laser down the middle of the arena. Then the arena widens open and phase 2 begins.

Phase 2 has the same health as phase 1 and is debatably harder. For starters, she has a jump attack where she'll slide across each half of the room. Which side she slides across first is telegraphed by a large splat effect on one half of the screen. When she uses her suck attack, circle around her as the tears she draws in and spits out are blocked by her body. Lastly, when she summons lines of tears you can see a faint outline showing where the next like will appear. Avoid using slowing effects on her during this attack as it will cause some tears to become unavoidable. Again, she is not as tanky as Hush so Mother can be melted down much easier, but it's good to preserve health and consumables while in Corpse the best you can.

Part 6: Repentance Secrets (2/2)

The Ascent Completion Marks
A whole bunch of 'em.
The Ascent is a sequence described towards the end of Part 1 that has you go from Mausoleum II all the way back up to Basement I. If you need to full clear any of these tiny Floors for supplies, I'd recommend the Depths and Caves as Mausoleum has tough enemies and the Basement is when the deadly Tainted enemies become very common. One trick you can use for the Ascent is to skip Treasure Rooms to get an easy Planetarium early in the run and then visit the skipped Treasure Rooms on your way back up.

Once you make it to Home, you'll have a chance to prep before fighting Dogma, the Ultra Harbingers, and finally the Beast. While none of these bosses are as difficult as Mother or Delirium; it's a marathon of boss fights so stock up on hearts and consumables while you can. Luckily, you do get a bed to heal before starting the fight with Dogma and get a partial heal and one-time use shield before taking on the Ultra Harbingers. All Characters must clear the entirety of the Ascent sequence to obtain one last Completion Mark.

Let's start with Dogma first. Dogma's fight is split between two phases, both with a "DPS Cap". In the first phase, you must destroy the TV that Dogma is connected to. Dogma fires multiple kinds of tear attacks. One such attack has the tears create electrical arcs on the ground you need to move off of. Another fires slow-moving Godhead tears that are easy to dodge, but standing in the auras too long will cause a white laser to instantly hit you. These attacks are mostly easy with some practice, but the brimstone laser is the tough one. Dogma will fire the laser in a cardinal direction and slowly home in on you, but will instantly swap to another cardinal direction if you move that way. You have to very carefully bait Dogma to swap the laser direction back and forth while staying in one of the corners. The TV has low HP so this phase is overall not too long or painful.

Once the TV is destroyed, Dogma will be freed and turn into an angel. At this point, their attacks are either the stupid ring attack or not the stupid ring attack. The non-ring attacks are bullet patterns and a ball of light you need to avoid the rays of. The STUPID ring attack on the other hand has Dogma fling themselves across the room wildly at you while unleashing bullet bursts. This attack is really hard to avoid in my opinion and almost always guarantees one hit. The ring will seek you out directly, so avoid moving diagonally so that the ring moves in more predictable cardinal directions. Effects that knock enemies back or slow them down are very much appreciated at this point.

Once Dogma is down and the cutscene has played, you begin your shoot 'em up style encounters with the Ultra Harbingers and the Beast (all with "DPS Caps"). The Ultra Harbingers each have halfway points similar to their regular fights and have relatively low HPs. One-time effects last for all of these fights and active items recharge between fights so you should have the resources you need to stand your ground through the gauntlet:

• You first face Ultra Famine, who will chuck flies at you and launch bullets that linger over time. Once he's halfway down, he'll sit in the middle while unleashing a relentless clusters of bullets until dead. Burst down this 2nd phase as fast as possible as it's very difficult to dodge around.
  
  
• Then Ultra Pestilence will vomit tears that leave poison clouds and launch a maggot that flies past the screen multiple times. Once halfway, Pestilence coughs up large tears and fly clusters until dead. If you keep the various fly summons out of your way, Pestilence is an easy fight.
  
  
• Ultra War is next, who chucks huge bombs that explode into tear bursts. He'll sometimes fly across the lava and launch magma balls in the air that you need to weave between. Once halfway, War will try to dash at you and launch flames or use a bomb to bounce himself around the arena. Once War is dead, he WILL explode and this can hurt you. Overall, try to stay clear of War as many of his attacks are more dangerous the closer you are.
  
  
• Ultra Death stands as the last Harbinger (Conquest and the Headless Horseman must be on vacation) and is the toughest of them all. Death does not have a halfway point, but rather swaps between 3 attack patterns. At first, he'll encircle the arena with scythes that will close in on you. Destroy the one closest to you and use that to loop around and not get caged in. Next, Death will summon and army of skulls you need to slowly weave between. Lastly, Death will go invisible and indicate with an eye flash when he's about to strike (and when you should dodge last second).
  
  
• Lastly, you're face to face with the Beast. Ironically, the Beast is maybe the easiest part of the entire Ascent. First, the Beast chases you through rock spikes. These are easy to fly between, but some will fall if damaged so be sure to look ahead just in case this occurs. Once the chase is done, the Beast will suck in fire rings you need to dodge through. Then you need to go up high quickly as she unleashes a huge laser and then flips to face the other way. On subsequent chases, she can use a different attack at the end, but these are easier to dodge and rare to begin with. After the Beast is low enough, she'll begin one final infinite chase as you whittle down the last of her HP and finally clear the Ascent. Consider that Completion Mark earned after all this crap.

Charged Penny and Old Capacitor
They will charge you up... for a small fee.
Battery Bums are a new type of beggar that frequently show up in arcades. Donating coins to them will result in your active item occasionally being charged up. Like other beggars, if enough is donated they will drop a battery-themed item. Do this 5 times and you'll unlock the Charged Penny trinket. Alternatively, you can blow them up to kill them. Do this 10 times and you'll unlock the Old Capacitor trinket.

Brimstone Bombs
Kill Hornfel before he escapes!
After reaching Chapter II: Mines (see Part 1), one of the bosses you can encounter is Hornfel. This boss rides a minecart the whole time, but defeating him will knock him out of his cart. The fight is now over, but Hornel will attempt to run away. If you kill him before he escapes then you get some extra pickups and this Secret.

Mega Mush
Beat everything in Hard Mode as every character.
The final boss of why I told you to always play on Hard Mode at the start of all of this. You need to have done every Completion Mark on Hard/Greedier Mode with EVERY Character. If you want a strategy for this Secret, try reading almost everything else in this guide.

Member Card and Golden Razor
You're one big spender!
Member Card and Golden Razor require you to amass up to 40 or 99 coins respectively and spend them all at one Shop. The easiest way to spend this much money in one Shop is Greed Mode, but amassing that much money is difficult. My personal advice is to play as the Keeper and look for a restock machine along with the 2 of Diamonds card to hit a huge shop. Ironically, the Member Card is an item that opens access to a second Shop with much more expensive items that can make unlocking the Golden Razor a breeze.

Death Certificate
...
This Secret has the exact same unlock requirements as Mega Mush, but in addition requires all Hard Mode Completion Marks for the Tainted Characters (see Part 2.5). Getting this item is a very good sign that full completion of this game is within your grasp.

Part 7: Challenge Secrets (1/4)

There are 45 Challenges in the game. Challenges are special presets to the game that give you a unique set of starting items and abilities. Most Challenges make the game harder, but some make it easier or just really weird. Challenges almost always ban Treasure Rooms and also do not allow progression on other non-Challenge Secrets.

Some Challenges must be unlocked and all Challenges unlock an item upon completion. I will list each Challenge, how to unlock it, what it unlocks, end goal, difficulty, and general advice of my own. I hid the spoiler end goals and unlocks for some Challenges, but you'll be good to look if you're all done with Part 1.

Rebirth Challenges

1. Pitch Black
How to Unlock: Already unlocked.
Unlocks: Rune of Hagalaz (rune consumable)
Goal: Mom
Difficulty: Easy
Advice: Pitch Black's two main mechanics are in the form of curses already in the game. For the entire run, you cannot see your health and rooms are darkened significantly. However, the allowance of Treasure Rooms, easy end goal, and lack of any other modifiers effectively make Pitch Black a normal run where you need to watch your health a little more carefully.

2. High Brow
How to Unlock: Already unlocked.
Unlocks: Rune of Jera (rune consumable)
Goal: Mom
Difficulty: Easy
Advice: The first, but not last, poop-themed Challenge. You start with several poop-themed items and Number One. Your range is a bit low with Number One and not getting many additional items to mitigate this is tough, but getting to Mom is more than doable with this set of items.

3. Head Trauma
How to Unlock: Already unlocked.
Unlocks: Rune of Ehwaz (rune consumable)
Goal: Mom
Difficulty: Medium
Advice: The difficulty of this Challenge mostly comes down to how good you are at using Tiny Planet's orbiting tears. The combination of this item and Soy Milk makes it so that you are forced to adjust to how Tiny Planet affects your tears in order to do any kind of damage. Luckily, only needing to beat Mom means you're never forced to fight tougher enemies or bosses with this setup. Don't try to hit enemies behind you because high tears = knockback. Instead, take the time to understand where you need to stand for Tiny Planet to hit enemies and this one shouldn't be too awful.

4. Darkness Falls
How to Unlock: Clear Chapter VI: Chest as Eve.
Unlocks: Rune of Dagaz (rune consumable)
Goal: Satan
Difficulty: Easy
Advice: In Darkness Falls, you play as Eve with her normal setup and a few other items that boost dmg or rely on getting hit. The items given to you are some nice picks and very strong in Eve's high-risk, high-reward playstyle. They more than make up for the lack of Treasure Rooms. Reminder that ♥♥♥♥♥ of Babylon only cares about how many red hearts you have, so stocking up on soul hearts is recommended if you're not confident in clearing the later floors at low HPs.

5. The Tank
How to Unlock: Have 7 or more red heart containers at once.
Unlocks: Rune of Ansuz (rune consumable)
Goal: Mom
Difficulty: Easy
Advice: In this Challenge, you play as Magdalene with several health items, the projectile blocking Infamy, and Thunder Thighs. Basically, you are very slow in this Challenge, but can put up with a lot of punishment. Slow speeds in Isaac can be an issue, but Thunder Thighs will clear obstacles in your way and it's not the worst stat to be low in. Plus, you can still obtain speed ups from boss items or other sources. Trust me, this is NOT the Challenge where melee enemies overwhelming you is a huge problem (see Challenge #22).

6. Solar System
How to Unlock: Defeat Mom's Heart 3 times.
Unlocks: Rune of Perthro (rune consumable)
Goal: Mom's Heart
Difficulty: Hard
Advice: In this Challenge, you cannot shoot tears and instead rely on a series of fly familiars orbiting around you to block and deal damage. On the plus side, you start with flying and the "Beelzebub" Transformation, which makes amassing pickups and friendly flies on early floors easier. However, some particular room layouts and bosses can really highlight how limited this form of attack is. Your damage is really capped and some enemies/bosses on Chapter III and IV can be painful endurance tests. Utilize friendly flies and bombs to make up for this and use flight to hover above obstacles whenever possible; let the enemies come to you. I recommend opening every Shop you can as items such as Hive Mind or BFFs can make this Challenge much more manageable.

7. Suicide King
How to Unlock: Defeat Mom's Heart 11 times.
Unlocks: Suicide King (card consumable)
Goal: Isaac
Difficulty: Easy
Advice: You now play as the Suicide King. You fire slow moving explosive tears that have the minor quirk of flying right back at you if you miss. Your starting items are more than powerful enough to handle most threats, it's not blowing yourself up that's the issue. It's important to note that Ipecac tears explode on contact with enemies, even if they sometimes seem way too high to hit the enemies. Honestly the way Isaac calculates tear height is weird and you shouldn't trust the visuals. Just take your time with your shots, this isn't the only Challenge that will ask you to aim carefully so better learn it now rather than later. You play as Lazarus, who always has an extra revive every floor which provides enough room for mistakes to make this Challenge surprisingly easy.

8. Cat Got Your Tongue
How to Unlock: Gain the "Guppy" Transformation
Unlocks: Rune of Algiz (rune consumable)
Goal: Mom
Difficulty: Medium
Advice: I call this Challenge "Solar System Lite". Once again, you are flying and cannot shoot and instead rely on gimmicky items to deal damage. The differences start with you being "Guppy" instead, a far more powerful Transformation (see Part 3). Starting out, your damage will be through the friendly flies created by hitting enemies with Guppy's Hairball. This item swings around you, so you need to sort of drag it through enemies. Once you do, you deal damage but more importantly generate flies. Save your Guppy's Head to clear up enemies that you cannot easily hit with the hairball. Your hope with this Challenge is to obtain a familiar or other damage dealing item that allows you to use "Guppy" to its fullest potential.

9. Demo Man
How to Unlock: Defeat Mom's Heart 9 times.
Unlocks: Chaos Card (card consumable)
Goal: Mom's Heart
Difficulty: Easy
Advice: You start this Challenge with Dr. Fetus and the Remote Detonator. One is a powerful, but risky item and the other is an item that eliminates the risk factor. Dr. Fetus will now spew an endless supply of bombs that are safe until you decide they aren't. Upon using Remote Detonator, any bombs you've placed will explode. You can hit a rhythm of chucking a bomb or two at an enemy and instantly detonating it. Once learnt, this is a powerhouse build that's strong enough to carry you all the way to Mom's Heart.

10. Cursed!
How to Unlock: Have 7 or more red heart containers at once.
Unlocks: Credit Card (card consumable)
Goal: Mom
Difficulty: Easy
Advice: You are now Cursed! You play as Magdalene with extra health and a full map. However, every single door you pass through deals damage to you. Because you can see the full map at all times, it's very easy to plan a path to the Boss Room that limits the amount of doors you cross through. Use bombs to open up Secret Rooms and destroy doors to further minimize damage, and this almost becomes like a normal trip to the end of Chapter III.

Part 7: Challenge Secrets (2/4)

11. Glass Cannon
How to Unlock: Beat Challenge #19 and unlock Loki's Horns (see Part 3).
Unlocks: Rules Card (card consumable)
Goal: Satan
Difficulty: Easy
Advice: Not to be confused with the active item, you are a Glass Cannon due to your low starting health as Judas. This is combined with an attack that drops targeted air strikes, sometimes in all 4 cardinal directions, that can one-shot you. While it is very easy to die early in this Challenge, what makes this one not too bad is that you're never limited on how much health you can have. If you do survive the early game you can amass a supply of soul hearts and defensive items that mitigate the low starting health. This is made easier by having effectively unlimited bombs to destroy tinted rocks and open Secret Rooms with. I'd avoid luck increases as they make Loki's Horns activate more often, which is frequently not worth the danger it puts you in.

12. When Life Gives You Lemons
How to Unlock: Already unlocked.
Unlocks: Card Against Humanity (card consumable)
Goal: Mom
Difficulty: Easy
Advice: In this run you start a with the Lemon Mishap active item and some item charge passives. Lemon Mishap is not really an amazing active item to work with, but the damage can be quite nice against slow moving enemies and bosses. What makes this Challenge easy is the lack of any other complications. You really just replace Treasure Rooms with a fast-charging Lemon Mishap and that's literally it.

13. Beans!
How to Unlock: Already unlocked.
Unlocks: Burnt Penny (trinket)
Goal: Mom
Difficulty: Easy
Advice: You play as Isaac and are not allowed to shoot tears, but start with Pyro (99 bombs) and Butt Bombs as well as a few poison bean items. Rely on The Bean's poison damage to kill slow or less dangerous enemies, and save your bombs for room-clearing with Butt Bombs or killing bosses. Your goal is to never run low on bombs since only using The Bean for later bosses is difficult. Luckily, 99 bombs should be enough to get you to Mom if you're being resourceful.

14. It's In The Cards
How to Unlock: Already unlocked.
Unlocks: SMB Super Fan (passive item)
Goal: Mom
Difficulty: Easy
Advice: You have an enhanced ability to generate and hold onto card consumables. Luckily, most of the card consumables are pretty good and having easy access to them is powerful. Once you learn how to best use utilize even just the tarot cards, this one's easy.

15. Slow Roll
How to Unlock: Already unlocked.
Unlocks: Swallowed Penny (trinket)
Goal: Mom
Difficulty: Easy
Advice: In Slow Roll, you have very, very slow firing tears with a small range (due to My Reflection) that deal like a billion damage. These stats are locked and cannot be increased or decreased. Luckily, these tears do pierce, so this Challenge becomes a test of patience. You can one-shot just about any enemy, but you need to lump them up and avoid hitting obstacles or you'll get overwhelmed. Any items that mimic your tears' stats are extremely useful as is gaining spectral tears to not worry about obstacles. Take your time and don't panic with this run and you'll be at Mom in... some amount of time.

16. Computer Savvy
How to Unlock: Already unlocked.
Unlocks: Robo-Baby 2.0 (passive item)
Goal: Mom
Difficulty: Very Easy
Advice: The rare example of a Challenge that is debatably easier than a normal run. Your damage is not very good, but you fire a homing lasers that hits every enemy in the room. As long as you can dodge enemy attacks while your laser barrage slowly melts everything in the room then this Challenge is basically free.

17. Waka Waka
How to Unlock: Already unlocked.
Unlocks: Death's Touch (very good passive item btw)
Goal: Mom
Difficulty: Hard
Advice: Oh yay my least favorite Rebirth Challenge! Solar System is probably harder, but Waka Waka boils my blood for some reason. Your tears are modified by anti-grav, which causes them to remain in the air and only launch forward when you stop firing. Strange Attractor on the other hand causes your tears and other attacks to pull enemies towards them at fast speeds. This means if you're not tap-firing, then you will be creating a line of tears that can and will slingshot enemies into you. The intended strategy is to create small lines of tears that enemies follow and take damage from, but careless firing can make this backfire and weird physics collisions can still occur even when being careful. Alternatively, you can tap-fire at closer ranges for lower damage output that's more consistent. Both options suck and the only saving grace is only having to make it to Mom.

18. The Host
How to Unlock: Already unlocked.
Unlocks: Tech .5 (passive item)
Goal: Mom
Difficulty: Easy
Advice: In this Challenge you start with Spiderbaby and The Mulligan. You have a random chance to spawn friendly flies upon damaging enemies and spawn friendly spiders upon getting hit. In essence, you are a budget "Guppy". This is far from the strongest set of starting items you can get, but much like with other Rebirth Challenges you benefit from an early end goal and lacking any other weird modifiers.

19. The Family Man
How to Unlock: Unlock Dad's Key (see Part 3).
Unlocks: Epic Fetus (passive item) and Challenge #11
Goal: Isaac
Difficulty: Medium
Advice: You start this Challenge with 3 familiars, Dad's Key, and BFFs (which massively buffs your 3 familiars). However, you cannot shoot tears and must rely on your familiars to do the damage. While Sister Maggy and Brother Bobby do respectable damage, the star of the show is Rotten Baby. This familiar with BFFs will spew out very high damage friendly flies at a fast rate. Still, it is difficult to make it all the way to Chapter V:Cathedral with this setup. Don't forget to take advantage of Dad's Key to open Shops, Secret Rooms, and other weird things like cheesing your way in/out of the Boss Rush. Shops especially can offer several bonus items to your familiars or other means of dealing damage in the event that Bobby isn't cutting it for you.

20. Purist
How to Unlock: Defeat Mom.
Unlocks: Rune of Berkano (rune consumable)
Goal: Mom's Heart
Difficulty: Medium
Advice: This Challenge seems like it's a lot harder that it is. You play as Isaac with no D6 or any other starting items and, as per usual, do not get Treasure Rooms. That's it. This is still of course a bit hard to work around, and failing to get good items from Devil Deals or other special sources can spell death. I'd advise playing to partway into Chapter II, and if you don't have a healthy supply of items then restarting. Once you do get a run going in this Challenge, it's pretty smooth sailing.

Afterbirth Challenges

21. XXXXXXXXL
How to Unlock: Defeat Mom.
Unlocks: Gold Hearts (pickup)
Goal: Mom's Heart
Difficulty: Annoying
Advice: In this Challenge, every single Floor is incredibly large. There's only one of the usual types of rooms (Treasure, Boss, Shop) and everything in-between is filler. Finding consumables or items that reveal the map such as XIX - The Sun can be a lifesaver and are essential to finding Secret Rooms. The amount of pickups you can gain from all the rooms as well as there being nothing in terms of a time limit makes this Challenge easy to trod through, but you will be there for a very long time (it took me roughly 2 hours on my attempt).

Part 7: Challenge Secrets (3/4)

22. SPEED!
How to Unlock: Defeat Mom.
Unlocks: Get Out Of Jail Free Card (card consumable)
Goal: Mom's Heart
Difficulty: Hard
Advice: Is it time for the hardest Afterbirth Challenge already?? In this run, you have 16 minutes. After that timer is up, you start to take damage at a quick rate until you die. While you can overpower this constant damage at first, it's unlikely you'll have enough healing to last forever. Luckily, you are very fast in this Challenge, BUT so is everything else. This can make many enemies much more difficult, and some faster melee enemies and bosses WILL overwhelm you and hit you at least once. You do get Treasure Rooms and Shops, so I would prioritize any items that can reduce the health loss of faster enemies hitting you, and map revealing Shop items that allow you to clear Floors quickly. My personal favorite pick is The Bible, which allows you to fly through rooms AND instantly kill both Mom and Mom's Heart. Still, the 16 minute timer is tight, so do not get discouraged if your first few runs do not go according to plan.

23. Blue Bomber
How to Unlock: Unlock Mr. Mega (see Part 3) and defeat Mom's Heart 11 times.
Unlocks: Gold Bombs (pickup)
Goal: Satan
Difficulty: Medium
Advice: In this Challenge, you play as ??? with Pyromaniac and Kamikaze! This allows you to infinitely blow yourself up without taking damage from it. This is your only form of damage outside of a Brother Bobby. The early Floors of this Challenge are easy as the explosion damage will kill most enemies with ease even if you have to get close to do it. Where matters get tricky is starting with Chapter IV. You start to get enemies and room layouts where running straight at the enemy is a bad idea. You can use bombs to deal with tankier enemies, but unfortunately your best bet is to stockpile soul hearts and get some speed up items earlier on to mitigate the sometimes unfortunate room layouts that are thrown at you. Fun Challenge, but there are definitely easier ones out there.

24. PAY TO PLAY
How to Unlock: Defeat Isaac as Cain.
Unlocks: Percs! and Addicted Pills (pill consumables)
Goal: Isaac
Difficulty: Medium
Advice: You start with 50 coins, Sack of Pennies, and an item that increases your damage based on your coin count. This is a very strong start, but there is a catch. Every door now costs one coin to enter and you die instantly if you ever run out of money. To make matters worse, getting hit will make you drop some of your money. This Challenge is where many Greed Donation Machine (see Part 4) and Keeper unlocks shine. The more items you can gain that generate money the better. Greed is good after all. I would avoid buying items from the Shop unless it directly generates money as it's often better to hold onto the 15 cents for safety and the damage increase. Despite what it seems, exploring every room on a Floor is a pretty solid idea as many room layouts can give chests and coin rewards that allow you to at least break even.

25. Have A Heart
How to Unlock: Defeat Mom.
Unlocks: Re-lax and ??? Pills (pill consumables)
Goal: Mom's Heart
Difficulty: Easy
Advice: You have 12 red heart containers, but start this challenge with only 1 full heart and Charm of the Vampire. This item will heal you half a heart after killing enough enemies. Every item or effect that drops red hearts will now drop pennies instead, and some items that heal you directly no longer work. Obviously the goal is to acquire health as once you heal all of those hearts you can snowball this Challenge pretty hard (you do get access to both Shops and Treasure Rooms). A good idea is to actually lose one heart container as soon as you can as it'll allow for other heart types to be picked up and grant you a better chance at cashing out those 12 heart containers for strong items in a Devil Deal. I'd take time to memorize some items that can heal you without spawning hearts such as XIX - The Sun. It'll be a skill VERY useful for later (see Challenge #34).

26. I RULE!
How to Unlock: Defeat Mega Satan.
Unlocks: Poker Chip (trinket)
Goal: Mega Satan
Difficulty: Easy
Advice: You start this Challenge with some utility items like The Ladder... as well as Mom's Knife. This is basically "Mom's Knife: The Challenge". It's a tricky item to get the timing down on, but one of the strongest damage dealers in the game that can carry you for almost the whole run. You do have to go very far into the run to beat this Challenge, but Trinity Shield making it so you block projectiles in the direction your stabbing enemies gives you ample time to learn the timing of Mom's Knife and ace the whole thing.

27. BRAINS!
How to Unlock: Defeat Isaac 5 times.
Unlocks: Stud Finder (trinket)
Goal: ???
Difficulty: Hard
Advice: In BRAINS!, you cannot shoot tears and instead rely on 3 copies of Bob's Brain to kill enemies. Bob's Brain has a certain reputation for being a familiar that does really respectable damage at the cost dealing full heart damage to you. Always take care in spacing yourself away from enemies as, even if you have no brains currently, your brains can respawn at any time and blow you up. Flying is very helpful for spacing yourself, and getting hit by enemies will grant you a few seconds to launch brains with no fear of retaliation. Much like Suicide King, dealing enough damage is never really the problem. Its being patient and skilled enough not to kill yourself. You do have the item Thunder Thighs, which allows you to break rocks for free and you gain access to the "Bob" Transformation; which provides a creep trail that can kill enemies too close for you to use the brains.

28. PRIDE DAY!
How to Unlock: Defeat Mom.
Unlocks: D8 (active item)
Goal: Mom's Heart
Difficulty: Easy
Advice: In what feels like a Rebirth Challenge, there are no weird rulesets to this one. You start with several items and a trinket that cause your tears to do all sorts of weird stuff including shot patterns and status effects. These effects are random, and will rotate every few seconds. Try firing and if the current effects make dealing damage difficult; stall the enemies for a few seconds and try again. Not much more to it than that.

29. Onan's Streak
How to Unlock: Defeat Mom's Heart 11 times and unlock Judas (see Part 2).
Unlocks: Kidney Stone (VERY good passive item btw)
Goal: Isaac
Difficulty: Medium
Advice: Remember in Suicide King when I said other Challenges will demand good aim? Well in this run you play as Judas with good damage and a charge shot item called Chocolate Milk. You have to make it decently far and have access to all types of rooms, but there is a catch. If you fire a tear that doesn't hit an enemy (or destructible obstacle), you take damage. Chocolate Milk allows you to decide when to shoot, but I recommend only attacking at close ranges. Allowing the tear to travel a long distance adds too many variables. Avoid items that spawn extra tears or take away the control that Chocolate Milk grants you. You deal very solid damage in this run, so if you've gotten your aim practice from similar Challenges then you should be able to move through with ease.

Part 7: Challenge Secrets (4/4)

30. The Guardian
How to Unlock: Defeat Mom.
Unlocks: Blank Rune (rune consumable)
Goal: Mom's Heart
Difficulty: Hard
Advice: In this Challenge, you cannot shoot but do have the Spear of Destiny that deals contact damage to enemies you point it at. You are flying and take no damage at all. However, you have a Punching Bag with Isaac's Heart behind that runs around the room. This is your new hitbox. Enemies will always prefer to target the Punching Bag over you if possible. The idea is to block shots and enemies that would damage the heart by physically shoving yourself in the way. The issue is that Punching Bag will move wherever it feels like and can often run straight into enemies or spikes. Outside of amassing a large amount of health and healing items, your best strategy is to learn enemy priorities. Find which enemies (usually melee enemies) are the most immediate threat to the heart and dispatch of them first. Make the best use of your flight and invulnerability to grab extra pickups and exploit curse rooms and donation machines. I find speed increasing items are almost essential as they increase your ability to respond to threats before too much damage is dealt. It's annoying having to babysit in this Challenge, but with the right bosses and room layouts it can be done.

Afterbirth+ Challenges

31. Backasswards
How to Unlock: Defeat Mega Satan.
Unlocks: Laz Bleeds More! (Lazarus starts with Anemic)
Goal: Basement I?
Difficulty: Medium
Advice: This Challenge is basically a Mega Satan check. It starts you with 10 random items at the Mega Satan fight. After the fight, you go back through the Floors while losing 1 item and heart container each Floor. The latter portion of this Challenge can be pretty easy if you can maintain your health. You've just gotta be able to beat Mega Satan with a potentially trash set of items (the R key is your friend). Luckily, this Challenge also creates a good opportunity to practice the fight a lot.

32. Aprils Fool
How to Unlock: Defeat Mom
Unlocks: Maggy Now Holds a Pill! (Magdalene starts with Full Health Pill)
Goal: Mom's Heart
Difficulty: Annoying
Advice: This Challenge does a lot to screw with player such as showing an incorrect map, randomizing pill and card effects, and many other small things. The hardest part of this Challenge is that every single boss all the way down to Chapter IV is The Bloat. Save your bombs for the first two Bloats and memorize the patterns of The Bloat (and its Champion forms). Then this Challenge isn't so bad, just annoying.

33. Pokey Mains
How to Unlock: Defeat Mom's Heart 11 times.
Unlocks: Charged Key (pickup)
Goal: Isaac
Difficulty: Easy
Advice: You start this Challenge with the Friendly Ball active item, but it works very differently than it does normally. You cannot capture enemies and instead summon a random friendly enemy upon being thrown. When a friendly enemy dies, your active item is instantly recharged. This can occur alongside normal charging methods allowing for multiple friendly enemies at a time. While not all enemies work well as allies, some can be quite powerful. This is all on top of a completely unrestricted ability to deal damage normally. While the setup is a bit weird, you're more than strong enough to clear the way to Chapter V.

34. Ultra Hard
How to Unlock: Defeat Mega Satan.
Unlocks: Samson Feels Healthy! (Samson start with the Child's Heart trinket)
Goal: Mega Satan
Difficulty: See Title
Advice: The Challenge makes every enemy and boss a champion, makes most Boss Rooms a double trouble boss fight, allows no hearts of any kind to be spawned from any source, enables every curse, and has you go to Mega Satan. It's a tall order. Make the best of non-heart drop healing you get from items like Book of Revelations (especially since you do get Treasure Rooms here). Always wait until low health for things like Rainbow Poop or a Full Health pill. Avoid curse rooms and Devil Deals as health is precious and the rewards are rarely worth it. The champion foes and curses are difficult, but it's mainly just the lack of hearts that makes this so tough. If you take too much damage in Chapters I and II then don't be ashamed to just restart.

35. Pong
How to Unlock: Defeat Isaac 5 times.
Unlocks: Greed's Gullet (passive item)
Goal: ???
Difficulty: Very Easy
Advice: This Challenge is a LOT like Slow Roll. However, despite the much further end goal, there a few aspects that make this one even easier. You are not limited in range by My Reflection and have Rubber Cement, which largely eliminates the issue of obstacles eating your shots. If you could beat Slow Roll, you can beat this one too.

Repentance Challenges

36. Scat Man
How to Unlock: Already unlocked.
Unlocks: Dirty Mind (passive item)
Goal: Mom
Difficulty: Unknown
Advice: Secrets yet to be uncovered...

37. Bloody Mary
How to Unlock: Defeat Mom's Heart 11 times, unlock Bethany (see Part 2), and unlock Blood Bag (see Part 3).
Unlocks: Sigil of Baphomet (trinket)
Goal: Satan
Difficulty: Unknown
Advice: Secrets yet to be uncovered...

38. Baptism By Fire
How to Unlock: Defeat Mom's Heart 11 times, clear Chapter V: Sheol as Bethany, and clear Chapter VI: Dark Room as Magdalene.
Unlocks: Purgatory (passive item)
Goal: Isaac
Difficulty: Unknown
Advice: Secrets yet to be uncovered...

39. Isaac's Awakening
How to Unlock: Defeat Mother.
Unlocks: Spirit Sword (SPEEN ITEM!)
Goal: Mother
Difficulty: Unknown
Advice: Secrets yet to be uncovered...

40. Seeing Double
How to Unlock: Unlock Jacob & Esau (see Part 2).
Unlocks: Broken Glasses (trinket)
Goal: Mom's Heart
Difficulty: Unknown
Advice: Secrets yet to be uncovered...

41. Pica Run
How to Unlock: Defeat Mom's Heart 11 times and unlock Marbles (see Part 5).
Unlocks: Ice Cube (trinket)
Goal: Isaac
Difficulty: Unknown
Advice: Secrets yet to be uncovered...

42. Hot Potato
How to Unlock: Unlock The Fettered (see Part ???).
Unlocks: VII - The Chariot? (card consumable)
Goal: Satan
Difficulty: Unknown
Advice: Secrets yet to be uncovered...

43. Cantripped!
How to Unlock: Unlock The Hoarder (see Part ???).
Unlocks: VIII - Justice? (card consumable)
Goal: Mom
Difficulty: Unknown
Advice: Secrets yet to be uncovered...

44. Red Redemption
How to Unlock: Unlock The Deserter (see Part ???).
Unlocks: IX - The Hermit? (card consumable)
Goal: Mother
Difficulty: Unknown
Advice: Secrets yet to be uncovered...

4!!!Five?. DELETE THIS@?!F
how t0

UNLOCK

: Ủ̷̖̝̜̿͊͂̈́̍̽̎̆͘n̵̢̟̮̮̱̺͗͂̓̈̎̀̓̓͋̏̋͐̓̌̕ḻ̶̦̯̜̪̮̫͕̬̙͒͛̐̒͝ͅọ̶̡͖͇̻͕̣̼̭̯̑̿̀͑́̐̚̚c̴̘͚̘͙̩̦̖̮̠̬̙͈͗̅̑̈́͜k̶̨̨̳̺̬͙̞̤͍̜̦̜̦̇̉͌̌̒̑̕ The Capricious (̷̟͕͈̘̖̼̲͜͝ͅs̶̟̀̀͂̓̔̊̈́̈͂̉́̐͋̅e̶̡͚͙̯͈̱͚͍͚̪͗̂́͊̈̍͒͛̏̅̀̈́͠͝͠ȅ̵̻͔͍̣̘̥ ̴̤͖̖͉̬̹͉̯̽̇̓́͋́̉̀͛͛̏͒̅̕P̶̢̭̟̝̾̃̎̽a̸̦̞̲̳͎̪͍̲̝͚͌̐̓̀r̶̮̠̲͎͕̼̺͎͉̬̬̈́̆͛̆̈́̒̉̈̑̈́͋̍̕t̷̨̡̜̠̩̫̹͕̰̹̦͖͉̉̆̑́̋̓̾͗ͅ???)̵͍̝͈̝͉̻́͑̄͘.̴̡̥̺̫̲̜͎̦̫̊

GGGG?L; ????????
CHALL*NGEE - FDS!!#@#36
AdVIIC3; ¡SɹƎ┴┴∀W פNIH┴ON

Part 8: Completion Secrets

Well, assuming you've done everything in this guide in order, you've finally made it. If you haven't, then let this section mark as several goalposts for you. There are 11 Completion Secrets in Repetance that follow relatively the same flow as this guide. These Secrets are the only ones in the game that unlock nothing. Your save slot icon can change according to these Secrets and some other important milestones, such as killing Mom. Some of the Completion Secrets are a bit bugged after so many DLCs and will unlock at weird times.

Perfect Chapter Secrets
A whole bunch of 'em.
Basement Boy, Spelunker Boy, Dark Boy, Mama's Boy, and Dead Boy are Secrets gained for clearing Chapters I, II, III, IV, and VI without taking a single hit. They don't actually unlock or change anything so that's why I'm including them here. I do not know why Chapter V does not have a Secret, but I'm not going to argue with it. Just as a note, damage of any kind counts against this, even soul hearts. The best way to get these Secrets is to just play The Lost, or generally have damage prevention items like the Holy Mantle as you basically get free hits. Avoid extra boss fights and events like the Boss Rush as they only serve to make this more difficult.

Golden God!
You are the best!
This is your first proper step in completion and requires completing both Chapter VI's.

!Platinum God!
OMG!
This Secret is unlocked when you get all 23 Endings the game has (most of them being the Mom's Heart ones) and all Rebirth Secrets EXCEPT for The Lost and his Character Completion Marks. Secrets and Completions Marks related to DLC areas or Characters are not needed.

The Real Platinum God
111% now stop playing!
Considered the full completion of Rebirth. This Secret is the same except it also includes unlocking The Lost and his non-DLC Completion Marks. This is harder than it sounds.

1001%
Nerd x 1000000
This Secret requires the unlocking of Real Platinum God as well as all Afterbirth Secrets and Completions Marks for their characters.

1000000%
Just Stop!
Unlock 1001% and THEN unlock every Secret from Afterbirth+, get every Completion mark for its Characters, and completely fill out the Bestiary (found in the Stats menu and most likely done long before you get here).

Dead God

The final goal of completing The Binding of Isaac: Rebirth. You need to have unlocked 1000000% and also have obtained Death Certificate and any other Repentance Secrets. Finally, you need to have picked up every single item in the game at least once. I'd recommend playing The Capricious (see Part 2.5) to do this last part as you can cycle items very quickly.

The Final Challenge...

"Wait what? How can there be more?!? I already gone beyond even 1 million percent completed for Isaac's sake!" I can hear you saying. Well, there's even more and it's not tied to a Secret. If you've already unlocked Dead God prior to reading this, you may already know what I mean by the Final Challenge.

After many events such as Completion Secrets or beating certain bosses, you'll see that your save file icon changes from when you start up the game changes. Upon getting Dead God, the game ushers its Final Challenge with your save slot icon depicting some strange figures. These figures will change their stance once 1000000% has been achieved on the given save slot:



To be clear the game is requesting that you 1000000% complete this game 2 more times for a total of 3000000% completion. Only THEN the game challenges you to unlock Dead God for every single save slot.

Now I love this game, but I can not stress enough how you SHOULD NOT DO THIS. I can't even begin to imagine the level of burnout you could suffer from this game by doing everything 2 more times. I know I will not be attempting this challenge; however, if you choose not to heed my advice then I'd love to know how the process for you is so feel free to comment on your progress. Again, there is no achievement tied to this challenge so I won't go into detail about any of it but it feels right to notify people of this option anyway.

Here's what the reward of Final Challenge looks like if you wish to see:
Behold the ∞ Percent Completion!

Ending Thoughts & Update Log

Thank you for reading (or skimming) through this guide all the way to the end! I swear it's not intentional, but I keep topping myself for the level of work that goes into the guides I make so the fact that people actually read them means a lot to me!

That doesn't mean I won't be updating this guide though. If you notice any grammatical or factual errors in my guide or have your own completion methods, let me know in the comments or elsewhere. I want this guide to be the best it can be so helping me out is greatly appreciated. I will keep an update log below this so you can know what has been changed prior to this guide's release.

Update Log:

4/6/2021 - Rebirth, Afterbirth, and some of the Afterbirth+ sections done. Guide is officially released!

May 2021 to January 2022 - Occasional minor updates for new information, comment suggestions, and all that fun stuff.

2/19/2022 - ??? Update: Updated some aspects of the guide to allow for Repentance content. Added sections to Part 1 and Part 2. Added Part 2.5. Began work on the Challenges for next update.

11/20/2023 - After a long, long break from playing Isaac and Steam as a whole, formatting changes were made to the guide in order to prepare for the Challenges and AB+ updates coming hopefully soon.

6/12/2024 - Undead Guide Update: I didn't actually die! I'm planning on finishing this original premise of this guide soon, but for now enjoy the entirety of Part 5: Afterbirth+ being finally complete!

6/19/2024 - Challenges Update: All Rebirth, Afterbirth, and AB+ Challenges are fully detailed in Part 7! This marks the completion of my original intention of this guide all those years ago. You can follow this guide and fully complete Isaac up to AB+.

Now obviously there is still Repentance to handle, but I'm going to take my time on that as I've still yet to complete that expansion and there are updates to it planned to release sometime this year. Thank you all for your patience with my horrendous update speed, and enjoy the journey of 1,000,000% completion!

7/24/2024 - Repenting Update: After making a ton more progress into Repentance, I've decided to bite the bullet and reformat for Repentance. The guide has been retroactively updated a ton of previous content to now frame Repentance as the current DLC as opposed to Afterbirth+. Expect more Repentance entries soon...

7/25/2024 - I really did mean soon! The section for Repentance Secrets that are not related to Part 2.5 or Challenges is now done. This section actually doesn't cover very many of the Repentance Secrets beyond the two new Completion Marks you can earn, but that's because Parts 1, 2, and 2.5 did a lot of the work for me already.

[mr no]

WTF IS TS NOT LETTING ME GET ACHIEVEMENTS PLS HELP ( I DISABLED ALL MODS AND DELETED THEM )

[Dragonova]

In the works, I've been going through MOST of the challenges again if that's any indication of the next update

[Chasvik]

Awesome guide! Update for this anytime soon?

[Dragonova]

Thank you for finding it

[SinQ]

I think you dropped this, king

[Dragonova]

The DPS cap is more of a soft limit and it's very doable to burst through it, but you'll likely never one shot bosses like Hush. As for the Repentance guide, life got very busy for me over the past months. I do have plans to finish this guide as a whole, but it may not be soon

[Sapphire ♥]

just a question but is it possible to bypass the damage cap? because i feel like i have because sometimes i have played as a character and when i fought hush very fast

[Dragonova]

Youre welcome

[S!XMachinE]

great info, tks

[Shinji Hirako]

mega satan