Breaking Cain

A comprehensive guide on how to utterly break the game as Tainted Cain, make almost any item in the game, and get completion marks as any character easily.

Updated for version 1.7.7

Introduction

The Binding of Isaac: Repentance added "tainted" versions of every character to the game, handily doubling the total character count. One of these characters, Tainted Cain, has a strange gimmick where he cannot pick up any items; instead, they explode into pickups Tainted Cain can use to craft items instead. This gives Tainted Cain an unparalleled level of control over which items he acquires, and with it, the potential to break the game wide open.

The potential of Tainted Cain is incredible. It takes a long time to set a breaking run up, but once accomplished, he can be used to easily win any run and add almost any item to the collection page. This makes him incredibly useful for earning stray achievements.

Tainted Cain is exclusive to The Binding of Isaac: Repentance. If you do not own the Repentance expansion, you obviously will not be able to take advantage of this guide.

What Can Tainted Cain Do?

• Easily clear any run as himself.
  
• Use the Clicker to turn into any other character and easily clear a run as them.
  
• Obtain almost any item in the game, thereby adding it to the Collection page for achievement purposes.
  
• Generate specific item combinations for clearing certain difficult achievements.

What Can't Tainted Cain Do?

• Help you clear Challenges or Daily Runs.
  
• Acquire certain uncraftable items.

Note that as of version 1.7.7, the methods by which to break the game have changed pretty dramatically; the D1 received a hefty nerf and is no longer sufficient for the job, though still important for getting things started.

Unlocking Cain and Tainted Cain

If you're relatively new to The Binding of Isaac, I recommend bookmarking this guide for later and just playing on your own for a while. If you really want to beeline for Tainted Cain, this section will detail how to unlock him as quickly as possible.

Unlocking Regular Cain

Regular Cain can be unlocked by holding at least 55 cents at any time. You will need regular Cain to unlock Tainted Cain.

Unlocking Tainted Cain

Unlocking tainted characters is a long process, reserved for the very end of The Binding of Isaac's unlock order.

1. Defeating Mom in Depths II for the first time will end the game and unlock the Womb.
   
2. Defeating Mom's Heart in Womb II ten times will unlock a new area called "???", also referred to as the Blue Womb. On subsequent playthroughs, defeating Mom's Heart (or its replacement, It Lives!) before the timer reaches 30:00 will cause a path to the Blue Womb to open up. Here, you will fight a powerful boss named Hush.
   
3. Defeating Hush three times will cause a new door to appear on subsequent playthroughs whenever you defeat the boss of Basement I. This leads to an alternate set of levels, based on the Antibirth fan mod.
   
4. Navigating the Antibirth levels is tricky; you may want to look at a separate guide to learn how to acquire the Knife Pieces and reach the Corpse. At the end of the Antibirth path, you will fight Mother. Defeating Mother for the first time will cause a strange door to appear at the beginning of Depths II in all subsequent playthroughs of the regular path.
   
5. Bring either the Polaroid or the Negative to this door. This will consume the item and unlock the strange door. Note that you normally cannot leave the boss room after defeating Mom; you will need to have some way to teleport out before you go in and fight Mom. Somewhere on the floor you can find a skull with an X-shaped crack in it; breaking it will always reward you with a 0 - The Fool card.
   
6. Behind the strange door is a hole to a special Mausoleum floor. The boss room contains no boss; only an item, Dad's Note. Picking it up will begin the Ascent. During the Ascent, you'll fight your way back up through modified versions of all the previous floors. At the end you'll reach a special floor called Home. Here, in Mom's bedroom, you'll find a chest containing the Red Key, which will also unlock the Red Key for future playthroughs. Using the Red Key on the reddish door outline in the hallway outside Mom's bedroom will unlock a secret closet containing the tainted version of whichever character you're playing as. If you're playing as Cain, you'll unlock Tainted Cain; if not, you'll have to do it again as Cain on a later playthrough.
   
7. The Red Key is not guaranteed to appear in subsequent playthroughs; to unlock subsequent tainted characters, leave any Trinket in a boss room on your way down to Dad's Note (this can even include the "boss" room containing Dad's Note). During the Ascent, those Trinkets will get transformed into a Cracked Key, a single-use consumable version of the Red Key. You can bring this Cracked Key up to Home to unlock more tainted characters.

Unlocking Important Items

With a few exceptions, Tainted Cain cannot craft items you have not unlocked yet; following their recipe will just give you something else instead.

Depending on how you intend to break the game, you may require some of the following items.

For breaking the main game, you will want the following items unlocked:

• D1. This can be unlocked by completing Greedier Mode as Isaac. Note that Greedier Mode itself must be unlocked by donating a total of 500 cents to the Greed Donation Machine in regular Greed Mode, if you haven't done that yet. Ironically, despite its connection to Greed Mode, you do not need the D1 to break Greed Mode.
  
• The Clear Rune performs the effect of your currently-held Rune without consuming it. It is unlocked by clearing Challenge #30.
  
• The Rune of Jera is unlocked by clearing Challenge #2.
  
• The Schoolbag allows you to carry two Active Items at the same time. It is unlocked entering six shops in a single run; Basement I to Depths II will provide exactly six, provided none of the floors bear Curse of the Labyrinth.

If you intend to break Greed Mode, you only really need one particular item:

• Birthright is mandatory for breaking Greed Mode, and very useful (though not mandatory) for breaking the regular mode. It can be unlocked by completing the Chest as Jacob & Esau, who are themselves unlocked by clearing the Corpse for the first time.

All other necessary items are available by default, but the more stuff you have unlocked, the more you'll be able to accomplish.

Playing as Tainted Cain

If you already know how to play as Tainted Cain and are just looking for how to break the game as him, you may skip this section.

Tainted Cain is tricky. Whenever he tries to pick up an item pedestal, the item will explode into pickups such as Pennies, Keys, Bombs, and Red Hearts. The only items exempt from this are certain "story" items such as the Polaroid, the Negative, Dad's Note, ect., and items found via certain special circumstances.

Tainted Cain starts out with a Bag of Crafting permanently in his consumable slot. If you pick up a regular consumable, such as a Pill or Card, you can switch between it and the bag by tapping the drop consumable key (Ctrl by default).

Tapping the key to use your consumable (Q by default) while the Bag of Crafting is chosen will let Tainted Cain pull his bag out, and pressing an attack key after that will swing the bag in that direction. Swinging the bag at pickups will scoop them up into the bag. The currently held pickups can be seen next to the Bag of Crafting. They cannot be spilled out of the bag; once an item is scooped into the bag, for all intents and purposes it's been destroyed, so think twice before scooping. Besides every variety of coin, heart, key, and bomb, you can also scoop up Cards, Pills, Runes, and batteries.

The bag can hold up to eight pickups. Once you have eight, an item will be displayed next to the Bag of Crafting to display what item will be produced with those ingredients. By holding down Q, Tainted Cain will take some time to make the item; once done, you will acquire the listed item. Note that aside from a few special recipes, Tainted Cain cannot craft items the player has not unlocked yet; their crafting recipes will instead produce something else.

If you scoop up pickups while you already have eight items in the bag, the pickup in the top-left corner will be destroyed and replaced with the new pickup. You can rotate which pickup is in the top-left slot by tapping Ctrl.

If Tainted Cain crafts an Active Item while he already has an Active Item, the old Active Item will immediately explode into pickups to make room for the new one. Be cautious, there's no way to undo this other than just re-crafting the old item.

Normally, the types of pickups released from a burst item pedestal are a fairly random assortment of common pickups, but bursting an item pedestal in certain rooms will always produce certain results:

• Item pedestals in Angel Rooms will always drop an Eternal Heart.
  
• Item pedestals in Devil Rooms will always drop a Black Heart.
  
• Item pedestals in Secret Rooms and (most) Super Secret Rooms will always drop a Bone Heart if they're unlocked.
  
• Item pedestals in Curse Rooms will always drop a Rotten Heart if they're unlocked.

Using the above-mentioned fact that newly crafted Active Items will destroy your previously held Active Item, you can exploit this to force rare types of hearts to spawn. Note that other room types, including Planetariums, Shops, and Boss Rooms, are not guaranteed to drop anything out of the ordinary.

Bag of Crafting Recipes

Crafting recipes are no longer static as of version 1.7.5; now, they're determined by the run's seed. Thankfully, the fine folk at the Platinum God website have produced a calculator of sorts. It can be found here, and is critical for this guide.

https://platinumgod.co.uk/bag-of-crafting/index.html

First, you must enter a run's seed; this can be found by pressing Esc to pause the game. Enter it into the calculator, and click the button to confirm it. Then, scroll down to the section titled Recipe Generator; this is where we'll be finding what recipes will create what items.

The calculator will only generate recipes using the pickups selected. A few pickups are already selected for you. Be careful not to select too many pickups, this can cause the website to slow down or hang. Play around with it if you like, and learn how to use it. We'll be using it a lot.

At the bottom of the webpage you will see several "fixed recipes", most of them involving eight of the same ingredient; these crafting recipes are always the same no matter your seed. Note that these fixed recipes aren't the only way to craft the listed items, they also have randomized recipes like everything else.

Breaking Greed Mode

Breaking the regular game and breaking Greed Mode follow two different methods. Breaking Greed Mode is a lot simpler than breaking the regular game, so I'll quickly cover it first. You can skip this if you intend to break the regular game.

Note that while it's simpler, it's also a lot harder now. I honestly don't recommend doing this anymore, but I'll document it anyway.

As stated, breaking Greed Mode (and Greedier Mode) works a little differently from breaking the regular game. Instead of using the D1 to make duplicates of pickups, you'll just be making tons and tons of random pickups and sifting through them for useful ones.

First, prep the Bag of Crafting calculator if you haven't done so already. Enter your run's seed, and select a handful of pickups; for now, only select Red Hearts, Pennies, Keys, Bombs, Cards, and Pills. Other, more exotic ingredients can be added to the calculator as they're acquired; if you get lucky and find one naturally, feel free to add it.

Making Steam Sale

The first order of business is crafting a Steam Sale for yourself. Find the Steam Sale in the calculator, and check out its recipes; you will probably need at least one Pill or Card. Try to pick a recipe that only requires one. Check the shop to see if the correct one is being sold. If it's not, hold R to reset the run and try again. Remember to enter the new seed.

Tainted Cain starts with a key in his inventory so he has access to both the gold item room and the silver item room. Touch the item pedestals in both to make them burst into pickups; count the hearts, keys, and bombs you get from them and compare them to your recipe; ideally, the only thing you need now are coins, both for the recipe and for buying a Card or Pill. If not, hold R to reset the run and try again.

Play the first floor of Greed Mode if you need to collect more coins, and craft the Steam Sale. Now all items in the shop are half-off, with all collectibles being 7 cents instead of 15 cents.

Eventually you'll want to make three more Steam Sales to reduce the price of all shop items to a measly 3 cents. If you can craft a second Steam Sale, do so now. Otherwise, it's time to worry about Birthright.

Making Birthright

Birthright is critical here in Greed Mode; without it, you won't be able to sustain yourself. It usually requires Soul Hearts, so add those to the crafting calculator if you haven't already.

Soul Hearts are tricky to come by in Greed Mode; if the shop isn't selling them, you'll need to either use the Restock Machine or advance to the next floor in hopes of finding them there. This will make or break your run; Greed Mode is going to get more and more difficult the longer you go without crafting anything useful.

Now that you hopefully have Birthright, all item pedestals will explode into more pickups than usual when touched. Try and craft those extra Steam Sales now if you can. You may notice now that it only costs 3 cents to buy the infinitely-restocking items, yet they almost always explode into more than 3 cents. Congratulations, you've officially broken the game. Keep buying items to generate more pickups, including more money to buy items with.

Some pickups are rarer than others; you may have to buy many items before one shows up. The room will gradually fill more and more with excess pickups such as Red Hearts, Keys, and Bombs. If you need to clear these out, just scoop 'em up with your Bag of Crafting; you might even randomly stumble upon a useful crafting recipe in the process. Occasionally you'll get a Troll Bomb or worse, a Golden Troll Bomb. We can deal with those eventually, hopefully before they become a problem.

Breaking the Regular Game - The D1 and Car Battery

Breaking the regular game and breaking Greed Mode follow two different methods. This section will focus on the regular game.

First, prep the Bag of Crafting calculator if you haven't done so already. Enter your run's seed, and select a handful of pickups; for now, only select Red Hearts, Soul Hearts, Pennies, Keys, Bombs, Cards, and Pills. Other, more exotic ingredients can be added to the calculator as they're acquired; if you get lucky and find one naturally, feel free to add it.

As you play, try to avoid picking up any pickups unless absolutely necessary (Hearts to heal yourself, Keys to unlock doors, ect.). Leave them laying on the ground until you've completed every room on the floor.

If you happen to find a Rune laying around, pick it up (with your hands, not your bag) and hang onto it for now; it's a surprise tool that will help you later.

Making the D1

Your first goal is to craft the D1; not only is it necessary for the break itself, it's also just extremely useful for setting things up to begin with.

Search the calculator for the D1. If it's grayed out, you don't have enough pickups selected. It usually requires three or more Soul Hearts. Pick a recipe you think you could work toward, and start working on it. You may need to get lucky with the shop for Cards or Pills, and find a Tinted Rock to get some Soul Hearts.

It is unlikely you will assemble the full recipe on Basement I; once you've scooped up all the ingredients you can for the D1, you can carry them to Basement II and try again for the remaining ingredients. Don't forget to collect any stray pickups you avoided before leaving the floor; after all, if you aren't going to use them for crafting, you might as well just collect them the old-fashioned way so you have some Pennies, Keys, and Bombs for later.

You should hopefully be able to complete the D1 recipe on either Basement II or Caves I; if you have to go deeper than that, you may want to just reset and start over before the game gets too hard to survive without useful items.

Once you have the D1, it can be used to copy any pickup in the room. The duplicated pickup is random; the only way to guarantee duplicating the pickup you want is if it's the only pickup in the room. Note that the copy won't be a perfect replica; copying hearts will give you hearts, and copying coins will give you coins, but the variety you get is random. Even so, this is still useful; using the D1 on a Red Heart has a chance of earning you a Soul Heart, for example.

Making the Car Battery

Your next step is to create the Car Battery

Once again, find the Car Battery on the calculator, and pick a recipe that you like. Thankfully, its recipes tend to be a little easier than the D1's. Speaking of which, now that you have the D1, you can use it to help make the Car Battery. Try using it on pickups such as Cards or Pills if you need multiple of them, or on Red Hearts to try and get Soul Hearts.

The Car Battery doubles the effect of your Active Item. In the case of the D1, that means every time you use the D1, it will produce two additional copies of a pickup in the room.

Breaking the Regular Game - Batteries

Getting Some Batteries

Your next step is to find a battery; any kind will do for now.

The most likely place to find a Lil' Battery is the shop, which may be selling them. You may also be lucky enough to simply find one laying around as a room reward clear, or find a 48 Hour Energy! Pill which will generate several Lil' Batteries on use.

If you cannot find any batteries naturally, you can generate a few by crafting the Battery Pack.

Besides recharging your Active Item, it will also spawn several random batteries around you. If you must rely on the Battery Pack for generating a battery, I recommend crafting it in a room around the center of the map, rather than out on the fringes; you'll be visiting this room often.

Note that once you find or make some batteries, the floor you're currently on will be your base for the next hour or two; if it has any extremely annoying rooms you'll have to run through frequently or a really uncomfortable layout, you may consider going deeper to the next floor, but don't push your luck by going too deep. Having a Curse Room is also desirable, if the floor has it. Be sure to try and find the Secret Room and Super Secret Room if you can.

Managing Your Batteries

Use the D1 on your batteries. Two more batteries should get generated, of random type. You can pick these batteries up to recharge your D1, and use it again; depending on the size of the batteries, you can either "break even" or "make a profit". Let's break it down:

• Generating two Micro Batteries is breaking even. Your D1 has a 4-room charge and Micro Batteries restore 2 charges each, so you're right back where you started.
  
• Generating one Micro Battery and one Lil' Battery is making a small profit. The Lil' Battery will fully charge your D1 on its own, letting you keep the Micro Battery. Be careful not to waste charge by picking up a Lil' Battery when a Micro Battery will do.
  
• Generating two Lil' Batteries is even better. Now you can use one to recharge the D1 while keeping an entire Lil' Battery as a spare.
  
• Rarely, you'll get a Mega Battery. This is the jackpot. It'll recharge your D1 twice over, letting you use it twice without recharging.
  
• Occasionally you'll get a Golden Battery. You can use these if you like, but they're kind of a pain (literally). If you don't have health to spare I recommend just "destroying" them by scooping them up with your bag. Thankfully they're rare enough that you shouldn't run out of batteries due to them.

Just keep using the D1 until you've built up a decent stockpile of batteries. You don't need to flood the entire room with batteries (yet), but try to keep a good buffer so you don't accidentally bankrupt yourself.

Now that you have infinite batteries on demand, you can start using the D1 on other pickups in other rooms to try and get more stuff. We still have some more steps to go, however.

Breaking the Regular Game - Runes

Finding a Rune

The D1 has served you well, but we'll be switching to a different duplication method soon, for which we'll need a Rune or Soul Stone; if you haven't already found and picked one up, you'll need to find one now. Unfortunately, Runes are pretty rare; there are a few ways to force one to spawn, however:

• Rune Bag generates a Rune after clearing several rooms. It is unlocked by clearing the Cathedral as Lilith. This is the only reliable way to force a Rune to spawn, but you may need to craft the Red Key or D7 in order to have enough rooms to get a Rune. If you decide to use this method, make sure you have either the Schoolbag so you can hold a second Active Item, or have enough resources sitting around to re-craft the D1 once you're done getting a Rune.
  
• Tarot Cloth will generate a random Card or Rune when crafted.
  
• Polydactyly will generate a random Pill, Card, or Rune when crafted.

Once you get a Rune or Soul Stone move on to the next step.

Getting a Rune of Jera

If the Rune you found was a Rune of Jera, then congratulations, you've already completed this step; if not, we can take advantage of the D1's nerf to try and spawn one. Set your Rune down in an otherwise-empty room, preferably close to your battery room, and use the D1 on it. This will generate two more random Runes. Keep doing this until you get a Rune of Jera; don't be afraid to clear out excess Runes as necessary, most of them aren't going to be very helpful in the future.

Keep that Rune of Jera safe; if you lose it, you'll have to use the D1 to generate a new one.

Making the Clear Rune

The Clear Rune is an Active Item that mimics the effect of your currently held Rune without consuming it; in this case, it's a repeatable Rune of Jera.

In my experience, Clear Rune always requires at least one Bone Heart to be crafted. To force Bone Hearts to spawn, you will need to destroy your currently held Active Item in a Secret Room; if you have the Schoolbag you can do this with just Portable Slots while keeping your D1 safe, but if not, it's time to say goodbye to the D1. Be sure you have enough pickups scattered around the floor to be good for a while without the D1.

Now that you have the Clear Rune and a Rune of Jera, you can accurately replicate pickups, and even faster than the D1 could; the only downside is that the Clear Rune has a hefty 12-room charge between uses.

Go to your battery room and either consume or scoop up all the Micro Batteries so that only Lil' Batteries remain; we won't ever need Micro Batteries again. Make sure the Rune of Jera is your currently selected consumable item, and use the Clear Rune. Thanks to the Car Battery this won't just double the number of Lil' Batteries in the room, it should quadruple it. Now that 12-room charge is looking pretty inconsequential; with just one or two uses of the Clear Rune you can flood your room with Lil' Batteries. Don't go too overboard, though; if the room is so full that the batteries are shoving each other around like crazy, use your bag to scoop a few up and make space.

Congratulations, you've officially broken the game; you can now make perfect duplicates of every pickup you find, and craft any item. The next step will be actually getting a good variety of pickups to abuse.

Generating Pickups

While getting ahold of Red Hearts, Keys, Pennies, and other common pickups is easy, some pickup types are rarer. Maybe you got lucky and were able to find one of every useful pickup on the floor. Chances are you weren't, and will need to manually force a few to spawn. This section of the guide will talk about how to generate each type of resource, usually by crafting items.

First, let's do a quick overview on which crafting ingredients are even worth having.

• Red Hearts, Soul Hearts, Black Hearts, Eternal Hearts, Bone Hearts, Pennies, Nickels, Keys, Bombs, Lil' Batteries, Cards, Pills, and Runes are all critical. Please make a stockpile of each of these. You can get away with just these pickups, but if you want to go a little beyond that...
  
• Rotten Hearts are useful for making certain items from the Curse Room pool, but most of those items also have crafting recipes that don't require Rotten Hearts. These are nice to have but not mandatory for most purposes.
  
• Golden Hearts are strange in that two items (Fate and Mom's Ring) seem to always require Golden Hearts, but otherwise they're superfluous and unnecessary. Only bother with them if you absolutely need one of those two items for your collection.
  
• Micro Batteries, Lucky Pennies, Golden Keys, and Golden Bombs are difficult to acquire and not always necessary, so I recommend skipping them personally.
  
• Charged Keys, Giga Bombs, Mega Batteries, Dice Shards, Cracked Keys, Golden Pennies, Golden Pills, Golden Batteries, and Poop Nuggets are not only prohibitively rare, they're also completely unnecessary. Don't even bother unless you somehow find one by pure chance.

What you'll want to do is have a dedicated room for each resource; clear out any other pickups and use the Clear Rune to make a good stockpile of each resource. If you need more room, you can make the Red Key and use it to add more rooms to the floor.

If you need to generate a large amount of random pickups and don't care which types, some of the following can help:

• Even outside of special rooms, bursting item pedestals can give you a good quantity of crafting ingredients, including sometimes a chance at rare ingredients like Black or Eternal Hearts.
  
• Chests will pay out with pickups, and can be duplicated before opening with the Clear Rune. This is the most reliable way to get Gold Hearts, Golden Bombs, Golden Keys, and Charged Keys outside of Greed Mode.
  
• The D20 (Unlocked by clearing the Chest as Isaac) can reroll all pickups in the room randomly. Remember not to destroy your Clear Rune by crafting this.
  
• The Everything Jar (Unlocked by defeating The Beast as Eden) can be used to generate a very wide variety of pickups based on its charge level. However, reaching specific charge levels is difficult without rooms to fight enemies in.
  
• The Box will generate several random pickups when crafted, including a Pill and either a Card or Rune.
  
• VIII - Justice will generate a Red Heart, a Penny, a Bomb, and a Key on use.
  
• X - Wheel of Fortune, XIV - Temperance, and XX - Judgement will generate a Slot Machine, Blood Donation Machine, or Beggar respectively, all of which may pay out with pickups if interacted with or blown up.
  
• VIII - Justice? (Unlocked by clearing Challenge #43) will generate Golden Chests which can pay out with pickups.

Generating Pickups - Hearts

Red Hearts

Red Hearts are one of the more common items in the game; chances are you already have some sitting around on the floor, or can make some more by bursting an item pedestal.

Half Red Hearts are fine to use, and will count as a whole Red Heart in crafting. Double Red Hearts should not be used, as they count as two Red Hearts and can make certain recipes difficult or impossible to make. Blended Hearts should not be used either, as they count as both a Red Heart and a Soul Heart.

• Marrow will generate three Red Hearts when crafted. It is unlocked by clearing Womb II on Hard Mode as The Forgotten.
  
• Mr. Dolly will generate three hearts that can randomly be Red, Soul, or Black Hearts.
  
• VI - The Lovers will generate two Red Hearts on use, but you will need a way to generate cards first if you don't have one sitting around.
  
• Queen of Hearts (Unlocked by defeating Mega Satan with Tainted Magdalene) will generate a massive amount of Red Hearts.
  
• Hematemesis will generate several Red Hearts.

Soul Hearts

Soul Hearts are rarer to find than Red Hearts, but are an extremely common ingredient in crafting powerful items. Some recipes even call for five or six Soul Hearts. You will want a steady supply of them.

Half-Soul Hearts are fine, and will count as a whole Soul Heart in crafting. Once again, Blended Hearts should not be used.

• Squeezy will generate two Soul Hearts when crafted.
  
• Mr. Dolly will generate three hearts that can randomly be Red, Soul, or Black Hearts. Try not to craft this item too often, as the Range Up it provides can cause problems in excess.
  
• Mom's Pearl has a chance of replacing new Red Hearts with Soul Hearts. This is more useful in Greed Mode, where making item pedestals explode into pickups generates many new hearts.
  
• V - The Hierophant will generate two Soul Hearts on use, but you will need a way to generate cards first if you don't have one sitting around.

Black Hearts

Black Hearts are used to craft items from the Devil Room pool.

Bursting an item pedestal in a Devil Room will always generate a Black Heart, but due to the fleeting nature of Devil Rooms this is not a reliable way to farm Black Hearts unless you have an item that can keep the Devil Room open, or find a Devil Room using the Red Key.

• Mr. Dolly will generate three hearts that can randomly be Red, Soul, or Black Hearts. This is one of the few ways to semi-reliably generate Black Hearts outside of a Devil Room. Again, try not to go overboard on crafting this if you can avoid it, the Range Ups are problematic in excess.

Eternal Hearts

Eternal Hearts are used to craft items from the Angel Room pool.

Bursting an item pedestal in an Angel Room will always generate an Eternal Heart, but due to the fleeting nature of Angel Rooms this is not a reliable way to farm Eternal Hearts unless you have an item that can keep the Angel Room open, or find an Angel Room using the Red Key.

• Sworn Protector generates an Eternal Heart if it blocks ten enemy projectiles in a single room, but as its crafting recipe always requires an Eternal Heart to begin with, it's not helpful. Unlocking it is an ordeal, as it requires you defeat Hush as The Lost. If you're really desperate for an Eternal Heart, you can use Death Certificate to acquire a Sworn Protector without crafting one; more on Death Certificate later.

Gold Hearts

Gold Hearts are used to craft items from the Golden Chest pool. Note that Gold Hearts themselves must first be unlocked by clearing Challenge #21.

These are not worth your time unless you specifically need to craft Fate or Mom's Ring; everything else can be crafted without Golden Hearts. If you find a Golden Heart randomly keep it around, but don't feel pressured to create one.

• The Everything Jar (Unlocked by defeating The Beast as Eden) generates a Gold Heart when used at 9 charges, but reaching that exact level may prove difficult or even impossible.

Bone Hearts

Bone Hearts are used to craft items from the Secret Room pool. Note that Bone Hearts themselves must first be unlocked alongside The Forgotten.

Getting Bone Hearts is fairly easy; making an item pedestal burst in a Secret Room or Super Secret Room will always generate a Bone Heart. Note, however, that Super Secret Rooms that force a specific heart type to spawn (such as the Womb-style rooms full of Red Hearts) will override this. If for some reason you don't have access to a Secret Room or Super Secret Room, there's only one other way to force a Bone Heart to spawn.

• V - The Hierophant? (Unlocked by clearing Greedier Mode as Tainted Bethany) will generate two Bone Hearts on use, but you will need a way to generate cards first if you don't have one sitting around.

Rotten Hearts

Rotten Hearts are used to craft items from the Curse Room pool. Note that Rotten Hearts themselves must be unlocked by entering the Corpse for the first time.

Getting Rotten Hearts is fairly easy if the floor you're on has a Curse Room; making an item pedestal burst in a Curse Room will always generate a Rotten Heart. If you do not have a Curse Room available, then the only other way to get Rotten Hearts is to pray you get lucky with an item pedestal or a chest, or manage to spawn a Rotten Beggar using XX - Judgement.

Rotten Hearts are useful, but usually not mandatory.

Generating Pickups - Coins

Coins are somewhat different from other pickups in that most items that force coins to spawn have completely randomized results; there is no way to specifically force a Penny, Nickel, or Dime to spawn, for example. The following items can be used to spawn random denominations of coins.

• Pageant Boy will generate several random coins.
  
• Keeper's Sack (Unlocked by clearing the Corpse as Keeper) will generate three random coins and a Key.
  
• Soul of the Keeper (Unlocked by defeating Boss Rush and Hush as Tainted Keeper) will generate a large amount of random coins.

Pennies

Pennies are a very common resource, and can be found sitting around in most locations. Greed Mode always rewards you with Pennies for clearing waves, and you can bomb the shop donation machine if you're really desperate.

Double Pennies should not be used, as they count as two Pennies when scooped up and can make certain crafting recipes difficult or impossible to make.

Nickels

Nickels are rarer to find than Pennies. Many crafting recipes call upon Nickels, so having them available is important.

Most ways of forcing coins to spawn have a chance of spawning Nickels.

Dimes

Dimes are even rarer than Nickels. Thankfully, you usually don't need them for crafting as long as you have a good quantity of other rare ingredients.

Most ways of forcing coins to spawn have a very slim chance of spawning Dimes.

Lucky Pennies

Lucky Pennies are a rare type of coin. They must be unlocked first by donating 1 cent to the Greed Donation Machine. You don't need Lucky Pennies, but they are pretty helpful.

Most ways of forcing coins to spawn have a prohibitively small chance of spawning Lucky Pennies, which make them very difficult to spawn. There is one item that can specifically force a Lucky Penny to spawn, however:

• Dad's Lost Coin (Unlocked by clearing Greedier Mode as The Lost) will generate a Lucky Penny when crafted. This is the only guaranteed way to spawn a Lucky Penny, though unlocking the item is very difficult.

Golden Pennies

Golden Pennies are very rare. You can use them in crafting if you find one, but otherwise don't bother trying to acquire them. There's no way to force one to spawn.

Generating Pickups - Bombs

Bombs

Bombs are a common resource.

Double Bombs should not be used, as they count as two Bombs when scooped up and can make certain crafting recipes difficult or impossible to make.

• Match Book will generate several Bombs when crafted.

Golden Bombs

Golden Bombs are a rare version of Bombs unlocked by clearing Challenge #23.

You don't need Golden Bombs for any recipes, so you can probably skip them, but if you really want one...

• The Everything Jar (Unlocked by defeating The Beast as Eden) generates a Golden Bomb when used at 11 charges, but reaching that exact level may prove difficult or even impossible.

Giga Bombs

Giga Bombs are the rarest pickup in the game and only appear in very specific conditions, none of which you can easily replicate here. Don't bother.

Poop Nuggets

Poop Nuggets replace bombs for Tainted ??? and cannot be acquired by other characters without Clicker shenanigans. They aren't even useful in crafting anyway.

Generating Pickups - Keys

Keys

Keys are a common resource.

Key Rings should not be used, as they count as two Keys when scooped up and can make certain crafting recipes difficult or impossible to make.

• Latch Key will generate two Keys when crafted.

Golden Keys

Golden Keys are a rare version of Keys.

Unfortunately, there is no reliable way to generate Golden Keys. You don't need them anyway, so you can probably just skip them, but they don't hurt to have.

• The Everything Jar (Unlocked by defeating The Beast as Eden) generates a Golden Key when used at 10 charges, but reaching that exact level may prove difficult or even impossible.

Charged Keys

Charged Keys are a rare version of Keys unlocked by clearing Challenge #33.

Unfortunately, there is no reliable way to generate Charged Keys. You may wind up rarely spawning one from anything that generates keys, but for the most part there's not much reason to bother trying.

Generating Pickups - Batteries

Micro Battery

Micro Batteries are the smallest type of battery. You don't really need them anymore.

• Battery Pack generates several randomly sized batteries when crafted.

Lil' Battery

Despite the name, Lil' Batteries are the full-sized batteries. If you've made it this far you should already have a room full of them; indeed, many crafting recipes call upon Lil' Batteries, so having a big stockpile of them serves a secondary benefit.

• Battery Pack generates several randomly sized batteries when crafted.

Mega Battery

Mega Batteries are even bigger. If you were lucky enough to find Mega Batteries you can keep them around, but they're otherwise unnecessary.

Golden Battery

I don't like Golden Batteries. They damage you when you touch them, so having a room filled with them is just asking for disaster. If you're (un)fortunate enough to spawn one of these, I suggest just getting rid of it.

Generating Pickups - Consumables

Pills

Pills are a moderately rare consumable. Note that all Pills are the same in crafting, regardless of their color and effect. Horse Pills can be used too, and count the same as a regular Pill.

• PHD will, in addition to making all Pills positive, generate one Pill upon being crafted.
  
• Mom's Coin Purse will generate several Pills upon being crafted.
  
• Mom's Bottle of Pills can be used to generate as many Pills as desired, but as an Active Item you must be careful not to destroy your Clear Rune with it.
  
• Polydactyly will generate a random Pill, Card, or Rune when crafted.

Golden Pills

Golden Pills are a special type of Pill that counts as a separate item in crafting. There's no reliable way to force a Golden Pill to spawn and no recipes mandate them, so you can skip this one.

Cards

Cards are a moderately rare consumable. Note that all Cards are the same in crafting, regardless of their type. Emergency Contact counts as a Card.

• Booster Pack will generate three random Cards when crafted.
  
• Magic 8 Ball will generate a Card upon being crafted.
  
• Deck of Cards can be used to generate as many Cards as desired, but as an Active Item you must be careful not to destroy your Clear Rune with it.
  
• Tarot Cloth will generate a random Card or Rune when crafted.
  
• Polydactyly will generate a random Pill, Card, or Rune when crafted.

Runes

We already talked about generating Runes earlier, but it doesn't hurt to go over them again.

Runes are a moderately rare consumable used to craft items from the Planetarium pool. Note that all Runes are the same in crafting, regardless of their type. Soul stones also count as Runes.

• Rune Bag generates a Rune after clearing several rooms. It is unlocked by clearing the Cathedral as Lilith. This is the only reliable way to force a Rune to spawn, but you may need to craft the Red Key or D7 in order to have enough rooms to get a Rune.
  
• Tarot Cloth will generate a random Card or Rune when crafted.
  
• Polydactyly will generate a random Pill, Card, or Rune when crafted.

Dice Shards

Dice Shards are a very rare consumable. There's no way to force them to spawn, and no recipes require them, so ignore them unless you find one sitting around randomly.

Cracked Key

Cracked Keys are very rare consumables and there's no way to force them to spawn outside of the Ascent. If you find one by sheer luck, you may as well use them in crafting, but otherwise don't worry about them.

Useful Items

Besides generating more resources, some items are simply useful to have during the breaking process. They might not kill every enemy you meet or help you melt Delirium to sludge in record time, but they're all useful nonetheless.

This section of the guide will talk about items that are useful to craft early on, not because they make you powerful but because they make things more convenient while you're still trying to break the game. We'll talk about powerful item synergies later.

Useful Items - Schoolbag and Active Items

• Schoolbag allows you to carry two Active Items at once, and switch between them by tapping Ctrl. It can be unlocked by entering all six shops from Basement I to Depths II in a single run. This is extremely useful (almost mandatory, even) for breaking the main game, as it allows you to keep your D1 or Clear Rune while still using other useful Active Items. It is less important in Greed Mode, but it never hurts to have. Remember that when you craft a third Active Item, whichever of the two old items is currently selected is the one that'll explode into pickups; make sure it's not the D1 or Clear Rune.
  
• With a fixed crafting recipe of 8 pennies, Portable Slot is one of the simplest and easiest items in the game to craft. While you can use the slot itself if you like to try and generate some common pickups, the main reason to craft it is as a quick and easy way to destroy your current Active Item and spawn pickups in whatever room you desire. This lets you force Eternal Hearts, Black Hearts, Bone Hearts, and Rotten Hearts to spawn if you do this in the appropriate room type. Make a Portable Slot, gather the ingredients for a second Portable Slot, then go in the appropriate room and destroy your first Portable Slot by crafting the second. Repeat as necessary.
  
• Death Certificate is the best item in the game, in that it teleports you to a special area where you can find one of almost every item in the game. Normally you need to unlock Death Certificate by clearing everything as every character, but if you fill your bag with eight Bone Hearts, you can craft the Death Certificate without having to unlock it. In the Death Certificate zone, you can choose any one item to take without having to craft it. Tainted Cain doesn't necessarily need this, but it has some useful applications; for example, if you're having trouble getting Eternal Hearts, you could use Death Certificate to get a Sworn Protector and then use that to generate an Eternal Heart. You can craft as many Death Certificates as you like and repeatedly visit the special zone, but bear in mind that every time you take an item, all other items in the same room disappear, so you can't get everything from it.

Useful Items - Floor Navigation

These items will help make the current floor you're situated on more tolerable to navigate.

• The Black Candle will provide you immunity to floor curses, including any on the current floor. It is unlocked by donating 150 cents to the shop donation machine. If the floor you're using as your base has an annoying curse like Curse of Darkness or Curse of the Blind, you'll want to craft this as soon as possible.
  
• Any source of flight; the easiest to make without rare ingredients is Transcendence, which requires easy-to-acquire Bone Hearts and is unlocked just by clearing Womb II three times. If you already have access to Eternal Hearts, Black Hearts, or Gold Hearts, you can try making other flight-granting items such as Lord of the Pit, Spirit of the Night, Dead Dove, Holy Grail, Revelation, or Fate.
  
• The Mind is difficult to unlock, requiring you clear Sheol as The Lost, but it reveals the entire map and all Secret Rooms. If you do not have The Mind unlocked, you can simulate its effect with the Treasure Map, Blue Map, and The Compass combined.
  
• The Red Key lets you generate new rooms outside the normal map. It is unlocked when you open the chest in Mom's bedroom for the first time at the end of the Ascent. It is very helpful for breaking the game, as it allows you more rooms to store your pickups, and can lead to hidden Angel Rooms and Devil Rooms which can be used to reliably generate Eternal Hearts or Black Hearts if you weren't able to generate them otherwise. If you're bored you can use the Red Key to explore the entire 13x13 area of the floor, just be careful not to go out-of-bounds; if you generate a red door but the mini-map doesn't add a room, you've reached the edge of the map and should not go through the door lest you get trapped in the I Am Error room.

Useful Items - Trinket Generation and Smelting

Trinkets are useful too! If you've got room for an Active Item, you can create and then permanently smelt any Trinket in the game onto yourself.

• Mom's Box is an Active Item that generates a new Trinket every time it's used. With infinite batteries you should be able to use Mom's Box infinitely and generate every single Trinket in the game. You'll know you've scraped the bottom when it starts generating duplicates. I recommend setting aside a large, otherwise-empty room specifically for storing all your generated Trinkets until you're ready to smelt them.
  
• The Smelter is an Active Item that consumes your current Trinket and makes it permanent. It is unlocked by clearing Womb II on Hard Mode as Apollyon. If you've generated every Trinket in the game with Mom's Box, you can now also smelt every Trinket you want. Be cautioned that some Trinkets are detrimental to breaking the game and should not be held, let alone smelted; more on that later. Also remember you cannot hold the Clear Rune, Mom's Box, and the Smelter all at the same time, even with the Schoolbag; be careful not to destroy your Clear Rune if you're doing this in the regular game.
  
• Mom's Purse and Belly Button both allow you to carry two Trinkets at once, doubling the rate at which you can smelt Trinkets onto yourself. Note that they do not stack; even with both, you're limited to carrying two Trinkets at a time.

Useful Items - Managing Pickups

• The Battery allows you to to hold two full charges on your Active Items. This won't help you acquire anything you couldn't get otherwise, but it is an immense time-saver that lets you use the D1 or Clear Rune twice without returning to the battery room.
  
• PHD makes all Pills positive, which can be used with the Clear Rune or even Placebo to consume large amounts of beneficial pills.
  
• Polydactyly will allow you to carry two consumables of any type (Cards, Pills, Runes).
  
• The Paper Clip allows you to open Golden Chests without spending Keys. This can be very convenient if you've been mass-duplicating Golden Chests with the Clear Rune.
  
• The Moving Box can be used to move pickups or item pedestals from one room to another. It can be unlocked by using Pandora's Box in the Dark Room. You may find this useful if you have some pickups in a faraway room you want to move to a closer room.

Useful Items - Shop Exploitation

• Counterfeit Penny (Unlocked by playing the Shell Game 100 times) will sometimes grant you extra money when you pick up coins. You have access to infinite money, but that doesn't mean you can't speed things up by holding this Trinket.
  
• Deep Pockets increases your maximum coin count to 999. It is unlocked by clearing the Chest as Keeper. Money probably won't be an issue, but it does give you a bigger wallet for when you want to buy many expensive items from a shop or donate massive amounts of leftover money to donation machines.
  
• Restock will make shops continuously replace purchased items, albeit at higher prices. This is unnecessary in Greed Mode.
  
• Member Card, unlocked by spending 40 cents in a single shop, grants access to a special basement in each shop that contains additional items. Besides having more item pedestals to burst into pickups, the basement shop may also sell rare items such as Runes.

Useful Items - Self-Protection

• Holy Mantle is always one of the best items in the game, and here is no exception; besides being useful later on in the run, it will also allow you to avoid taking damage when venturing in and out of the Curse Room if you haven't filed the spikes off yet.
  
• Pyromaniac is another item that, besides being amazingly powerful later, will also help during the breaking process, protecting you from random explosions due to Troll Bombs or potentially your own bomb placements.
  
• Safety Scissors will defuse any Troll Bombs. This is extremely useful and extremely important in Greed Mode, where Golden Troll Bombs will wreak havoc endlessly if spawned from an item pedestal.
  
• Flat File will remove all spikes from the floor, spiky rocks, and even the Curse Room door, allowing safe access. Note that this will also make Sacrifice Rooms permanently unusable if you smelt the Flat File, so think twice before doing that.

Bad Items

Some items can impede your ability to properly break the game. Try to avoid crafting these items. Some Trinkets are problematic as well, and should not be smelted permanently into your inventory.

• Butter! should be avoided at all costs; its effect can cause Tainted Cain to drop his Bag of Crafting, permanently losing the ability to craft items.
  
• Error grants you a random Trinket effect each room, which can potentially include undesirable effects such as the aforementioned Butter! or other problematic Trinkets. It can be difficult to notice this Trinket laying on the ground, so be careful not to accidentally pick it up while smelting.
  
• Humbling Bundle, Equality!, and Bogo Bombs will cause certain pickups to become their doubled versions. This can make it difficult to get an odd number of them in your Bag of Crafting.
  
• Little Baggy and Starter Deck will turn all cards into pills or all pills into cards, respectively. Do not craft these unless you are willing to craft both of them. You're better off just crafting Polydactyly.
  
• Bum Friend, Dark Bum, Key Bum, and Bumbo should be avoided, as they will steal the pickups you have laying on the ground. Do not craft any of these unless you are absolutely certain you will not require their preferred pickups anymore.
  
• Cursed Penny teleports you every time you pick up a coin. As you'll be touching many coins (especially in Greed Mode), this effect will become aggravating very fast.
  
• Broken Remote, 'M, and Expansion Pack will cause undesirable effects when using your Active Item, making it very difficult to use the Clear Rune for pickup duplication.
  
• Magneto, Broken Magnet, and Super Magnet will pull pickups toward Isaac, potentially collecting them when you don't want to.
  
• GB Bug and Lil Portal can potentially reroll or consume pickups if mismanaged.
  
• Missing No. will reroll all your items every floor transition potentially ruining the entire purpose of your playthrough.
  
• Filigree Feather will prevent Angels from dropping Key Pieces. Only smelt this Trinket if you're certain you do not intend to fight Mega Satan.
  
• Bloody Penny, Burnt Penny, Flat Penny, and Blessed Penny can be mildly inconveniencing, by spawning foreign pickups when you collect coins. This isn't always a problem, and Blessed Penny can even help out if you can't find Soul Hearts, but I do not recommend smelting them if you still have work to do. Note that Counterfeit Penny does not have this problem, as it directly adds extra coins to your inventory instead of spawning them on the floor.
  
• Too many Range Up upgrades, be they items or pills. Believe it or not, Tainted Cain's Bag of Crafting works off the range stat, and the higher your stat the further in front of you the Bag of Crafting's hitbox will be. If you upgrade it too much, you'll have trouble scooping up pickups.
  
• While not caused by any one specific item, avoid item combinations that can cause a game crash, such as numerous processor-taxing flashy tear effects combined with a high rate of fire.
  
• This goes without saying, but obviously do not craft items or smelt Trinkets that you would not want to put up with later in the game; just about everything you make here is permanent, after all.

What Can You Do Now?

Now that you're capable of crafting any item in the game, it's time to get down to business. Consider why you're breaking the game, and decide what you want to do with this power at your fingertips. The upcoming sections of the guide will walk you through accomplishing any of these goals.

• Make yourself absurdly powerful.
  
• Clear almost all of Tainted Cain's completion marks in one run.
  
• Clear another character's completion marks.
  
• Exploit Eden's Blessing to make your next run start strong.
  
• Generate items missing from your item catalogue.
  
• Generate specific items needed for achievements.

Becoming Powerful

If you aren't just making items for your collection page or specific achievements, you probably want to become strong. This section will help you become the most powerful Tainted Cain (or other character!) you can be.

Be careful not to go too overboard on item synergies and flashy tear effects; you can potentially cause the game to crash just from trying to fire tears, and nobody wants that.

Becoming Powerful - Defensive Items

Making yourself utterly invincible is a good way to break the game. I recommend crafting several or even all of the following items, especially if you intend to use the Clicker to turn yourself into a fragile or difficult character such as Tainted Lost, Tainted Keeper, or Tainted Jacob.

• Holy Mantle was already discussed earlier, but if you haven't made it yet you may as well make it now. This is especially powerful if you intend to become Tainted Lost, who otherwise cannot obtain the Holy Mantle.
  
• The Wafer reduces all damage sources down to just half a heart of damage. In the Womb and beyond, this means you basically have double the health you'd normally have, assuming you even take any damage to begin with.
  
• Pyromaniac was also discussed earlier. Not only does it make you immune to explosions, it also heals you when you get blown up. If your character has Red Hearts, you can potentially make yourself invincible by pairing this item with Kamikaze or Dr. Fetus, but even just the explosion immunity on its own makes the game much easier.
  
• Dead Cat will grant you nine additional lives, at the expense of removing all but one of your Red Hearts; this isn't a problem, though, because you should have infinite Soul Hearts sitting around, and can just craft more health-granting items if desired. You can actually make as many Dead Cats as you like and gain even more lives. This item is very useful if you intend to become Tainted Lost, who otherwise has trouble finding extra lives, but it is not very useful as Tainted Eden, who will probably lose the Dead Cat if they get hit anyway.
  
• Psy Fly is a potent shield, intercepting any enemy projectiles launched your way. Remember that it cannot protect you from enemy Brimstone beams or certain other non-conventional attacks.
  
• 2Spooky will make nearby enemies suffer the Fear status and automatically run away from you. It won't help much against bosses, but it will practically guarantee immunity to contact damage from regular enemies, and is especially good paired with the aforementioned Psy Fly.
  
• Lost Contact makes your tears destroy enemy tears on collision. Pairing it with piercing tears, Brimstone, or Tech X lets you destroy a large swathe of incoming fire.
  
• Gnawed Leaf grants you total invulnerability as long as you stay still and don't attack. Pairing it with an auto-attacking familiar (Daddy Long Legs would be the best in this case) can guarantee a victory, but it's also incredibly slow.
  
• Stop Watch permanently slows down all enemies and their projectiles to 80% speed. Unlocking it requires you donate the maximum of 999 coins to the Shop Donation Machine.
  
• Evil Charm grants immunity to status conditions. These aren't common, but the best asset it provides is immunity to the toxic gas often encountered in the Corpse or when fighting Ultra Pestilence. It also protects you from Dogma's Godhead tears' auras.
  
• Blind Rage greatly increases the duration of mercy invincibility you get after taking damage. It won't help you as characters who cannot take damage at all, such as Tainted Lost, but it will help everybody else avoid taking more than one stray hit at a time.
  Book of Shadows and 4.5 Volt together allow you to achieve total invincibility; Book of Shadows makes you invincible for 30 seconds (or 60 with the Car Battery), while the 4.5 Volt allows you to recharge the book by dealing damage to enemies. With a powerful build, you'll deal damage fast enough to stay permanently invincible during long boss battles such as Delirium or Mother. This is especially potent as Tainted Lost.

Becoming Powerful - Offensive Items

Let's be real here, everybody has their preferred synergies and powerful items. Instead of listing every single good item in the game, I will list the items I personally like to use, and the order in which I craft them. You are free to experiment with your own setups.

• Rock Bottom is a good way to start any powerful build, as it prevents your stats from ever going down, only up. Note that the exact way Rock Bottom works is a little more complicated than that, but if you follow this order you should be fine. Bear in mind you must first unlock Rock Bottom by clearing Boss Rush as Jacob & Esau
  
• The Book of Belial will be our main source of damage upgrades, believe it or not. Instead of wasting our time crafting damage-ups like Cricket's Head or Polyphemus one at a time, we're going to shoot right for the top. Go to your battery room (or make a battery room, if you're playing Greed Mode), use the Clear Rune to produce an absolute tidal wave of Lil' Batteries, then switch to the Book of Belial and start spamming it without leaving the room. If you run low on batteries, just make more. Your damage stat will keep increasing and increasing endlessly, as high as you want it to go; I find a value around 100 to be sufficient. Because of Rock Bottom, our damage will stay this high, instead of falling back down when we leave the room.
  
• Even with the nerfs it received in Repentance, Tech X is still one of the best tear replacements in the game. It will serve as the basis of our combo.
  
• Brimstone is next, and you can actually craft a second Brimstone if you want your Tech X + Brimstone shots to be thicker.
  
• Soy Milk synergizes with Tech X. Now instead of having to charge up shots, simply holding down the fire button will let you release an endless barrage of rings, all with 100+ damage; Rock Bottom nullifies Soy Milk's massive damage down.
  
• Mutant Spider will take our already-broken Tech X barrage and quadruple it with no downside thanks to Rock Bottom. You can craft a second Mutant Spider if desired, for even more shots.
  
• Spoon Bender or any other source of homing tears will help curve the beams toward enemies. It is hardly necessary at this point since your shots should be filling the entire room anyway, but it doesn't hurt.
  
• Terra allows your shots to destroy all obstacles in the room, reducing the need for Bombs.
  
• Uranus grants a freeze effect to your shots, turning killed enemies into ice statues. The main benefit of this is that it prevents enemies from doing anything bothersome in their death animations, such as splitting into smaller enemies, exploding, or releasing shots. It also makes your rings look cool, figuratively and literally.
  
• Holy Light gives your tears a chance to summon powerful beams of light. With a high Luck stat, you'll summon constant beams of light that'll absolutely shred apart anything that doesn't already get vaporized by the Tech X shots alone.
  
• If you're playing Greed Mode, craft Midas' Touch. It has a secret secondary effect of piercing Ultra Greed's boss armor.
  
• Believe it or not, the Trinket A Lighter can be ludicrously powerful if you were able to get your luck stat to 40 or higher by duplicating Luck Up Pills or Lucky Pennies. It should instantly kill all non-boss enemies the moment you enter any room.

This should be more than sufficient for defeating every enemy and boss in the game, but you can always stack more tear effects on top with items such as Sinus Infection or Jacob's Ladder. Remember that regular status effects, such as poison tears from Scorpio or fear tears from Dark Matter, have little effect on bosses, and every regular enemy should get pulped immediately by your shots (or A Lighter), making them somewhat superfluous.

Becoming Powerful - Navigational Items

Now that you're powerful and durable enough, it would be useful if you could navigate future floors with little inconvenience. These items should help you figure out where you're going. This is not as critical in Greed Mode.

• The Mind, unlocked by clearing Sheol as The Lost, will reveal the full map of every floor, including special rooms and secret rooms. With this, you can beeline for the exit of each floor, or take your time exploring every nook and cranny; the choice is yours. This item was mentioned before, but bears repeating. If you don't have this unlocked, Treasure Map, Blue Map, and the Compass grant its effect when combined.
  
• Black Candle grants immunity to floor curses, such as Curse of the Lost, Curse of the Maze, and Curse of Darkness; you may have already crafted this one too.
  
• Any flight-granting item. We've been over this one before as well. Why wouldn't you want to fly all the time?
  
• Rib of Greed will prevent future shops from containing Greed or Super Greed. This is useful if you intend to visit shops later for any reason.
  
• Broken Padlock allows you to open locked doors by bombing them instead of spending a key. However, it also has an extra effect of allowing you to bomb open the door to the Mausoleum, which normally requires you to take damage to open. This is mainly useful if you intend to go to the Mausoleum as Tainted Eden.

Completion Marks as Tainted Cain

With the amount of power you're now packing, Tainted Cain should be strong enough to beat any challenge in the game. Here are some tips on how to get the most bang for your buck. If you play your cards right and get a little lucky, you may even be able to clear all of Tainted Cain's marks except Greed Mode in a single run!

The R Key is critical to this. R Key is an Active Item that, when used, sends you back to Basement I while keeping all the items (and completion marks) you already obtained. Because Tainted Cain can craft as many R Keys as he wants, it means he can potentially cycle through the game indefinitely as long as you're able to make a new R Key before the end of each cycle. There are a few caveats to keep in mind, however.

Boss Rush and Hush

The timer does not reset when using the R Key; as you've probably been playing for at least an hour by now, this means Tainted Cain cannot access Boss Rush or Hush. The following items can help with that:

• Mama Mega is a one-time-use Active Item that can blow open the door to Boss Rush or Hush as long as you use it on the appropriate floor (Depths II or Mausoleum II for Boss Rush, Womb II for Hush). Since it's an Active Item, however, it competes for space with your R Keys or any other items you were hoping to bring with you.
  
• Strange Key is a Trinket unlocked by clearing Sheol, the Cathedral, the Dark Room, and the Chest as Tainted Eve. As long as you have it in your inventory, the door to Hush (but not Boss Rush) will be open regardless of how much time has passed. Note that the key's other purpose, giving you items when used in tandem with Pandora's Box, will remove the Strange Key from your inventory, so avoid Pandora's Box if you intend to fight Hush this way.

These will allow you to bypass the timer restrictions and clear Boss Rush and Hush no matter how long it takes. Carrying one Mama Mega and one Strange Key is much preferable to carrying two Mama Megas, so consider unlocking the Strange Key as Tainted Eve when you get the chance. That way, you can use your second Active Item slot to carry the R Key.

Note that you can also face Boss Rush on the Antibirth path, before the Corpse. If you don't have the Strange Key and want to keep an open slot for an R Key, you can clear Boss Rush on your Antibirth cycle and Hush on a different cycle, with one Mama Mega crafted for each.

The Beast

When you defeat The Beast at the end of the Ascent, the game will automatically end, with no opportunity to use an R Key. As such, The Beast should be the final cycle you complete.

Mega Satan

Unfortunately, Mega Satan has a similar problem; when you defeat Mega Satan, the game has a 50% chance of ending immediately, with no opportunity to R Key; the other 50% is opening a portal to the Void, in which case you are free to use your R Key (or go to the Void and fight Delirium first, if desired). Either way, Mega Satan should be the second-to-last completion mark you aim for, with the understanding that you may not be able to continue after.

Of course, reaching Mega Satan is a conundrum in itself; you require two Key Pieces, which can only be obtained from defeating the Angels in Angel Rooms. Thankfully, Key Pieces do not burst when Tainted Cain tries to pick them up.

Eucharist (Unlocked by clearing the Void as Magdalene) and The Stairway (Unlocked by clearing the Cathedral as Jacob & Esau) can be used to force Angel Rooms to appear at the end or beginning of floors, respectively. You probably do not need these to get enough Angel Rooms to appear, but it certainly does not hurt.

Dad's Key is an Active Item that can be used to force any door to open, including Mega Satan's door. If you don't want to fight the Angels, or if you smelted Filigree Feather against my advice, this is an alternative method to accessing Mega Satan. This is less preferable to simply assembling the real key, however, since it takes up an Active Item slot.

Recommended Order

Knowing what we know now, it is time to figure out what order both minimizes the number of cycles we need to complete, and runs the least risk of prematurely ending the game. I propose the following:

1. Hush, Cathedral, and the Chest. If you're lucky enough to get a portal to the Void after defeating ??? (20% chance), take it.
   
2. Antibirth path.
   
3. Sheol, Dark Room, and Mega Satan. If you didn't get the Void previously, pray you get it after Mega Satan (50% chance).
   
4. Ascent.

Boss Rush can be done on any of these runs, provided you make a Mama Mega.

If you really don't want to risk missing out on the Void and Delirium, you can alternatively go directly to the Void after defeating Hush, but then you'll have to make five total cycles instead of four, and you still may wind up ending the game after Mega Satan.

Completion Marks as Other Characters

This is the real holy grail of Binding of Isaac exploitation. So exploitative, in fact, that I'd only recommend doing this if you really don't care about earnestly challenging yourself and just want to cheat your way to victory.

Clicker is an Active Item that, when used, changes your current character to a different one, allowing you to set up a game-breaking run as Tainted Cain and then switch to a different character to win the run as them.

Be warned; turning into Tainted Isaac will remove all but your first eight (twelve if you have Birthright) items. Unfortunately, as of this writing I know no way around this. Worse, because Car Battery is making Clicker activate twice per use, every use has twice the chance to pass over Tainted Isaac and delete your items. If this happens, there's not much you can do but either try and become Tainted Cain again and re-craft everything, or just try and run through with the few items you've kept. Smelted Trinkets do not get removed, so if you smelted a lot of Trinkets you may actually still be decently powerful.

One thing to note is that using the Clicker as Tainted characters will only turn you into other Tainted characters, and using the Clicker to turn into regular characters will only turn you into regular characters. As such, Tainted Cain cannot become regular characters using the Clicker. However, there is a workaround; extra lives that revive you as a different character will allow you to become a regular character when you die and revive, from which you can then use the Clicker to become any other regular character. The items that allow this are Lazarus' Rags, Judas' Shadow, Ankh, and the Missing Poster Trinket. Note that due to how extra lives work, any extra lives from Dead Cat will be consumed before the aforementioned items' extra life, so sadly you cannot bring Dead Cat lives with you when becoming one of the regular characters.

Another note about the Clicker itself is that every time you use it, the most recent item you've collected will be removed, as a toll of sorts; because you (probably) have the Car Battery, however, two items will be removed. The last thing you want is to lose all those powerful items you crafted, so before you start using the Clicker, I recommend crafting a bunch of junk items you don't mind losing; scooping up 8 Keys will let you craft as many Latch Keys as you like, which can give you a good buffer of items to "spend" on Clicker uses.

One last note on the Clicker; Tainted Eden's items get shuffled every time they take damage; this has a strong chance of ruining your powerful item set, or worse, giving you an item set that just crashes the game outright. The door to the Mausoleum normally requires you take damage to open it, so if you're intending to clear the Antibirth path as Tainted Eden, you'll want to bring an alternative way of opening that door, such as Dad's Key or that Broken Padlock I mentioned earlier.

Now that you've used the Clicker to hopefully become an interesting character, you can proceed through the rest of the game as that character, and secure an easy victory. Note that since you need one Active Item slot for the Clicker, you only have one other slot for either a Mama Mega or an R Key. As such, you'll have to choose whether you want to go to Boss Rush or clear two runs back-to-back, unless you're lucky enough to find a Mama Mega or R Key naturally during the run.

Eden's Blessing

This is slightly less exploitative than using the Clicker.

Eden's Blessing is a craftable item unlocked by defeating Hush as Eden. It has a relatively minor effect of slightly boosting your Tears stat, but its real potential is hidden; the next time you start a new run (R Key does not count), you will begin with a random item.

A nifty bonus on its own, but Tainted Cain can exploit this; by crafting additional Eden's Blessings, you can start your next run with more items; ten is the limit.

Craft ten Eden's Blessings as Tainted Cain, and then finish your run (either as Tainted Cain or as somebody else; it doesn't matter. You can even die if you want, so long as the run is officially over). The next time you start a run as any character, you'll begin with ten items right off the bat. Which items you get is totally random, but you could potentially get something that easily lets you win even as a difficult character.

Crafting Items for Your Collection Page

One of the handiest uses for Tainted Cain is making items not for winning runs, but just for filling out your Collection page on the main menu; after all, obtaining every item is necessary for 100% completion. Some items such as Mega Blast, Delirious!, and Pyromaniac are just plain rarer than other items, so this is a good way to collect them for completion.

Note that not every item can be crafted; rather than talk about how to craft every single item in the game, I'll instead talk about which items cannot be crafted by Tainted Cain. Note that several of these can also be obtained using Chaos, Spindown Dice, or Death Certificate. Also remember that Tainted Cain himself cannot pick up any of these except for the story-related items or items in the Death Certificate zone.

• Story-related items: The Polaroid, The Negative, Key Pieces, Knife Pieces, Broken Shovel Pieces and Mom's Shovel, Dad's Note, and Dogma. Just playing the story should let you encounter these items naturally.
  
• Certain items specific to Tainted characters: Hold and Recall. These items are not included in the Collection page anyway.
  
• Specific payouts from machines: A Dollar (from Slot Machines), Crystal Ball (from Fortune Teller Machines), Blood Bag and IV Bag (from Blood Donation Machines), and Skatole (from Shell Games). These can only be obtained by playing their respective machine until it pays out with the desired item.
  
• Redemption. Sacrifice Rooms and Confessionals may pay out with this item if you've previously taken a Devil Deal.
  
• Head of the Keeper. The only way to find this is as a very rare drop chance when blowing up shopkeepers.
  
• The Small Rock. This is occasionally found when blowing up tinted rocks.
  
• Wait What? has a chance of replacing Butter Bean on any given run.
  
• Drops related to the Horsemen: Cube of Meat, Ball of Bandages, A Pony, and White Pony. Tainted Cain cannot craft these, but he can craft a Book of Revelations if for some reason you're having trouble encountering the Horsemen. Just remember you'll need to become somebody else before picking up the items.
  
• Steven. For some reason, this item cannot be crafted, only obtained from defeating the Steven boss 20% of the time.
  
• A Lump of Coal and Head of Krampus. These can only be obtained as drops from defeating Krampus.
  
• Broken Glass Cannon. Craft the regular Glass Cannon and then take damage while holding it.

Crafting Items for Specific Achievements

Some achievements from Afterbirth+'s booster packs are not related to defeating big bosses, but instead require you to find certain combinations of items within a single run. Due to the random nature of the game, it can be difficult and frustrating to actually get lucky enough to find these items. Thankfully, Tainted Cain comes to the rescue.

Huge Growth

Unlocking this achievement requires you grow in size five times within a single run. The easiest way is by finding a XI - Strength Card and duplicating it with the Clear Rune, then using it five times in the same room.

Moving Box

Unlocking this achievement requires you bring Pandora's Box all the way to the Dark Room and use it there. This one isn't too difficult to accomplish without Tainted Cain, but if you're having trouble getting lucky with a run that both includes Pandora's Box and is strong enough to reach the Dark Room, you can always use Tainted Cain to easily clear it. Note that repeatedly using a Sacrifice Room after the 12th use has a chance of just teleporting you directly to the Dark Room, if you don't care about the rest of the run.

Technology Zero

Unlocking this achievement requires you obtain two Technology items in a single run. Potential candidates include Technology, Technology 2, Tech X, Tech.5, Robo-Baby, and Robo-Baby 2.0.

Lachryphagy

Unlocking this achievement requires you to boost your tears stat ten times in a single run. Simply crafting ten of an item such as the Torn Photo will work, or eating ten Tears Up Pills if you happen to find one and can duplicate it with the Clear Rune.

Flat Stone

Unlocking this achievement requires you pick up the Rubber Cement item five times, total. If you're having trouble finding it in your runs, or just tend to avoid it due to disliking the item, you can craft it as many times as needed as Tainted Cain.

Marbles

Unlocking this achievement requires you use five Gulp! Pills in a single run, and is pretty difficult. Even if you break the game to amass infinite pills as Tainted Cain, there's no guarantee that Gulp! will be in the rotation that run. All you can do is keep trying. Remember that each run has 13 different Pill types available from the pool of 50. Also remember that Gulp! Pills themselves must be unlocked first by completing a Victory Lap.

If your run has Horf! pills, they get converted into Gulp! pills by PHD, Virgo, or Lucky Foot.

Baby-Bender

Unlocking this achievement requires you to stack the homing tears effect on yourself twice at the same time; once from a passive item such as Spoon Bender or Godhead, and a second time from using either a I - The Magician Card or Telepathy For Dummies. I recommend Spoon Bender and Telepathy For Dummies.

The Planetarium

Unlocking this achievement requires you obtain any three celestial items in a single run:

• Any of the eleven Planetarium items.
  
• Any of the twelve Zodiac-themed items.
  
• Zodiac (the item itself)
  
• Magic 8 Ball
  
• Crystal Ball
  
• Deck of Cards
  
• Tarot Cloth
  
• Echo Chamber
  
• Card Reading
  
• Star of Bethlehem

Conclusion

All in all, Tainted Cain really is a broken character if you know what you're doing. That being said, I wouldn't recommend relying on Tainted Cain for everything; if you don't bother to ever play as the really challenging characters legitimately, are you really getting your money's worth out of this game? After all, the whole point of this game is to be challenging, and at times frustrating, but worth it for the satisfaction of pulling off an amazing win or struggling against insurmountable odds. I personally prefer not to cheat with Tainted Cain, but I figured I'd document it anyway because it's fun, and because others may get good use out of this.

If you find any issues with my guide, such as a mistake or something that's ambiguously worded, please feel free to correct me or request elaboration.

[voice_caller]

yes

[LindyMan]

JESSE, WE NEED TO PLAY TAINTED CAIN JESSE

[Random Pug, Soviet Pug]

Yes I have bone hearts and the forgotten unlocked. It's less of a problem now that I realized that momma mega doesn't take bone hearts, but still, it's wacky. It could be from a mom but I only really have cosmetic mods

[The Inedible Hulk]

It should work with active items.

Do you have bone hearts unlocked?

[Random Pug, Soviet Pug]

I played a game with cain and kept crafting active items in secret rooms trying to get a bone heart. Does the generation only work with pedestal items?

[derplemonade]

Even though mods are not discussed in this guide, an external tool is already being used, and External Item Descriptions has a dedicated Bag of Crafting extension that displays what items can be crafted with the pickups on the floor. While it doesn't display all the recipes like Platinum God, that same feature makes it feel a bit less cheaty. Worth noting.

[The Inedible Hulk]

I've updated this guide to account for the changes version 1.7.7 made to the D1, among other things. You can still break the game, it just requires an extra step or two now!

[The Inedible Hulk]

Thank you for the notice. Hopefully they'll improve the seed reader to allow us to search recipes by item once you've entered a seed. That would be a huge help.

[Gryphus]

Hulk, yes, recipes can be determined using the run seed, in fact PlatinumGod has been already updated with an input for the seed run: https://platinumgod.co.uk/bag-of-crafting/index.html

The problem is that only 19 recipes are fixed, none of which are part of this exploit.

But if eventually we get a list of items, maybe it would still be doable, even if in a more time consuming way

[The Inedible Hulk]

Indeed, this guide will need tremendous revision-- if it's even viable at all.

I wonder if we can use the seed to determine a run's crafting recipes.