All you need to know (especially for Hardcore)

First things first - this is a written set of behaviours and things to be aware of, for being better. There won't be any 'must have' set of upgrades, list of secrets or videos/images to follow. When I write to 'learn' or 'remember' something, it's probably expectation, that you will get through game on Normal/Hard and get some lessons out of it before trying Hardcore.

Settings

There are two setting, which are very helpful in conserving ammunition and are OFF by default. These are "Enemy lifebar" and "Crosshair". First will help you conserve ammo, switching weapons to more adequate for the situations, second one will allow you for better aiming (so less ammo used for missed shots) and some sniping (if you unlock railgun for example).

Be always ready

You know expression "Itchy finger" or "Trigger happy"? Yeah, that's you know. Always expect enemies, no matter if it's beginning of level, opening a door or turning a corner. It's better to shoot once or twice in an empty corridor, than to get eaten by whatever is in it.

Strafe master

As on Normal difficulty you can quite often just stop, aim and shoot, on Hardcore stopping while in range of enemy attacks, will lead to your fast death. Especially with bosses, which often can 1hit you. Learn to run&gun and know where you're running, what leads us to...

Be aware of your surroundings

Sounds simple, but it's crucial. Most destructable objects are also unpassable, what means that you can block yourself on them and die fast. Just try to remember what is where.

Be aware of your equipment

Sounds simple, but it's worth noting. Pay attention to ammount of your ammo to different weapons, compared to ammo lying around. It's also important to control ammunition supply to your currently equipped weapon. When you run out of bullets and try to shoot again, your character will switch automatically to NEXT weapon. I have screwed my run many times because of running out of ammo for uzi and switching automatically to TNT while in close quarters combat. And also shotguns needs to be reloaded, so if you switch your weapon too early after shooting, shotgun will need to be reloaded after you switch back to it.

Be aware of your enemies

Many enemies won't be able to pass simple doors. Others won't be able to leave certain area (probably because of hitbox collision). Some won't be able to attack you, when you hug your backside to the corner of room. Many will have multiple health phases. And some of these can be cancelled, by using certain weapon or hitting certain spot to kill such enemy. I won't be listing all of these, as this would take too long. Also, believe it or not, most enemies have few hitboxes. For example a knight running to you and hiding behind his shield can still be killed, if you aim in his head, which sticks out.

Secrets

Try to look for secrets as often as possible. Not only to get additional ammunition hiding behind a fake wall, but also to get more experience for upgrade points.

Shortcuts - use them... but not really

So, shortcuts are fun and allow us to get through the level faster, right? Wrong! Shortcuts can make you skip other secrets or enemies to kill (and therefore - experience point). It's good to unlock a shortcut (it's still a secret, so it's giving you exp), but going through it... Nah. Also - never step up into teleport, without checking everything around first. You never know where it will throw you.

Pickups

Don't pick up everything mindlessly. If you're missing only 2 rounds in your uzi, don't pick up package of 50 rounds. Just be aware of it and use uzi for a time. Also remember, that you have only ONE life. Blue ankhs doesn't change it. The only thing these does, is healing you fully. So again, don't always pick them up, leave it as a safety precausion. Remember when you left it and go back when needed. Oh yeah, this means...

Don't be afraid of falling back

Combos doesn't matter, neither does your time on a level. So remember placing of health and ammo boxes, for which you can backtrack when needed. Also be friends with "Tactical retreat", as it's often easier to kill enemies when they chase you through some kind of chokepoint.

There are no bad wepaons...

...only the ones you don't like
Basically every weapon is strong and useful. Spamming dagger slashes blocks your enemy from attack. Charged shot with magic cane will 1hit most of enemies. Axe can be upgraded to use as life/mana stealer. Bolts to crossbow can be recovered after shooting. I could list every weapon like that, but again - you need to learn and understand your equipment, especially, that everyone has different preferences.

No refunds

When you buy a weapon upgrade or new spell, points cannot be returned. But there is a simple way around it - when you buy an upgrade, simply play with it in your workshop. Try shooting your 'new' weapon or spell to see if it meets your expectations. This will save you from having some crap, which you don't want to use. On my first run I made a mistake of NOT doing this and I was stuck with Nailgun which to my surprise was damaging myself too, when its bullets were bouncing from wall to wall.

My upgrades

As a small addition, here is the list my favourite upgrades and reasons why I chose them. The order is the same as in the upgrade station, not as I was getting them in-game:
AXE - Bloodthrist - Stealing HP, works great as a safety net.
Pistol - .50 Magnum - massive damage and headshots; easy for cancelling some multi-phase enemies.
Shotgun - Autoloader - when you have Magnum pistol, you don't need another long-range weapon, but massive damage with fast shooting is very useful.
Super Shotgun - Harvester - some enemies can't be killed by two shots of regular shotgun. Harverster is for such enemies.
Uzi - Akimbo - Double the damage. And Nailgun can damage yourself, what can be very problematic.
Minigun - Autoturret - You can leave it alone in some places where there are/will be many enemies. It will either help you fight or even fight for you. Also, very useful with bosses.
TNT - Hand Grenade - simply more damage in area
Rocket Launcher - Supersonic rockets - insta-hit of your target will ensure, that it won't run away until rocket gets to it.
Crossbow - Ballista - piercing your enemies is quite useful
Flamethrower - Firelance - For me, regular flamethrower was awful weapon, while firelance is one the best.
Laser gun - Railgun - very powerful sniper rifle. Can 1hit many enemies, can hit them precisely from far away and you can make it shoot faster when combined with Magic Light spell (shoot + click spell + shoot again; works similar to switching AWP to knife for a split second in 'good old' Counter-strike).


Regarding spells, besides free Magic Light, I bought only Sammoner, as it allowed me to add some ammo in crucial situations.

That's all folks

I think, I have listed every advice I can think of. If not, let me know in the comments and I can add it :) Hopefully, this guide will help you to get "Evil Nightmare" achievement. If so, remember about leaving a rating.

[MAG]

If you invest a lot into spirit, the stock staff becomes a true carry. Holding the fire button for a while makes a lazer beam capable of piercing throught all non boss ennemies. You can (relatively) easily beat the game on hardcore without firing a gun once, only using melee(Mana steal axe obviously), stock staff, storm rage, Holy Guard, and about 25 spirit. I recommend getting these perks in this order: Student, Thoughness, then either mana potential or the loot drop thingy.
Soul collector isnt really good, 5 mana per ennemy if you manage to catch the drop before it disappears.

[Камень]

A little trick to the freeze stuff - you can cancel it's animation by swapping wapons, or using spells. Frozen staff - Light spell combo makes it one of the most DPS weapons.

[Cerasza]

I'd prefer the lifesteal axe paired with the Soul Collecter perk, that way you can get both health and mana at the same time.

[UnprecedentedStudios]

Danyaell. I feel like you can just circumvent the freezing blast and just use Storms Rage (and with more points into spirit Holy Guard). No need to freeze the enemies when they all get vaporized by Storms Rage. How much does the mana Axe even steal and is it even worth it compared to the life leeching axe?

[Danyaell]

I have only played on hard so far, but don't sleep on spells. Storm Rage and Freezing Blast: those two combined wipe entire rooms of enemies. Also use the Axe to steal mana and you're all set.

[Krulla_Chief]

I'd say that Holy Shield is also the other spell that's uh, really worth buying at all. That extra defense is one hell of an extra guard in the middle of a monster hoard.

Also in general the Heavy Bolter is super useful for shredding either one big target, like a Boss, or a general group. Also, the Napalm Launcher is super good for peppering the floor. And also getting that one awesome bug where on fire enemies drop multiple drops.

Also, in general fire is a super useful tool when dealing with multi stage regular enemies because I've found that the enemies straight up do not enter their next stage most of the time if they're lit on fire. It's super clutch in the Hell stages because they don't want to die.

[SPRÆY]

yeee you can farm lol

[Lusians]

I have a questio can you still farm upgrade points and exp on single stages when you do hardcore run or that is a not posible?

[UnprecedentedStudios]

For those talking about Freeze Blast or Storm's Rage in the comments, I feel Storm's Rage is superior (except against bosses, where apparently Freeze Blast is usable somewhat).
Storm's Rage tracks any enemy through walls and lingers for a time. With enough points put into Spirit, Storm's Rage becomes a "I hate this room please deal with it for me" spell that can be combined with Holy Guard (especially in the Hell levels where mana is more abundant).

[Cerasza]

Probably obvious to anyone that's gotten far enough in the game to see it, but the Curse spell is a no-no, double damage output isn't worth doubling the already increased damage taken, it's just asking for death in most situations. While I wouldn't suggest prioritizing it, the shield spell can be somewhat useful as long as you remember that it's not a good replacement for dodging attacks, just lets you take a few more hits than you normally could.