Hi there!

I finished the game on normal and thoroughly enjoyed it, even if I found it a bit on the easy side (I died 5 times, one of which was because I missed the throw of a dynamyte stick and two falling in a lava pit), then I started Hardcore. Oh boy, the difficulty ramps up!
It would be perfectly fine if you had more than one try, but since you only live once...
I was wondering, what is your strategy to get through it? Upgrades, leveling, cheap tricks? I find myself contantly losing to the third form of the Sorcerer, he's just too fast and he skewers me in mere seconds without giving me pause. I find it especially difficult because by then the arsenal is still very limited, no heavy duty weapons available.

I added many stat points to health and only a few to strength, ammo and mana. Just enough to be able to get the toughness and sprinter perks before the first boss. Finding many secrets in the levels does help a lot making the Hardcore mode a little easier but it's still a good challenge.

I found all secrets. I use toughness and student, but maybe it is indeed better to try sprinter... I just upgrade health and capacity anyway. The few points in the other attributes might be sacrificed for the greater good, let me try...

What about weapons? I upgrade SMGs to akimbo and the pistol to big caliber, but maybe there is a better choice.

Yes akimbo SMGs are useful. I also upgraded the lightning staff. Works well against groups of enemies. The double barrel shotgun that you can find in the first castle level of E1 does also work well. I later upgraded it to a quad barrel shotgun, which does massive damage. Other upgrades I picked during the run were the faster minigun, the firelance upgrade for the flamethrower (very useful), faster rocket launcher and the railgun upgrade for the laser rifle.

I used the same upgrade path for normal, Firelance is probably the most powerful weapon of all... yet it burns out fuel very quickly as well. What about the normal shotgun, better improving power or rate of fire? I went for riot, but now I'm not sure.

I've found the slugs to be more useful, letting you drop medium enemies like the soldiers and melee robots in E4 at range, while if I was up close I'd want to be using the minigun or double barrel anyway, not the automatic shotgun.

Biggest help in my nearly successful hardcore run was actually the ice spell. Gives you something to use your mana on, lets you skip enemy phases, and slow or stop the much faster melee chargers. I would even recommend investing in some spirit to increase it's width and duration, which are both very noticeable if you compare it to casting it with no spirit [very thin line of freezing]

I went with the autoloader just because I like that upgrade a little more. But both are pretty cool. I would say it's really a personal decision. Using the BFG was also really helpful in the final hell levels. I wiped out a huge amout of enemies with it.

EDIT: IT IS DONE!

Whew, the Sorcerer is down. Sprinter was indeed the solution, coupled with the double barrel shotgun. Onwards!

EDIT: Damn! The Sphinx got me.

Getting instakilled by the lava in E5M5 was incredibly infuriating for me. I don't think I'll attempt Hardcore again anytime soon.

I mean, Hell in Hardcore is really tough and I had a couple of close calls, but instakill lava is just idiotic.

EDIT: FINALLY COMPLETED! It was a pain in the neck playing more than half of E5 in slow ass walking mode, but it was necessary due to the instant kill lava scattered throughout those levels. I have found the Lightning Staff to be not so useful, I preferred the upgraded Minigun, the BFG and the supersonic Rocket Launcher to deal with crowds. Essential, at least in the last episode, is the Flame Lance/Flak Cannon to melt Abominations and every monster with phases, as well as the Freeze Spell to keep Hellhounds and other fast enemies in check (or shatter them and skip the phases). Also, throwing preemptive Frag Grenades over walls where you know there is a monster closet helps a lot.

Also, Slugger is essential, at least it was for me, my go-to weapon for basically any situation. Never used the Laser Gun, even if upgraded, the Crossbow, the Staff (I really found it underwhelming anyway, Mana better spent on Freezing). SMG is very useful for when I hadn't the Minigun, but I stopped using it afterwards and never upgraded it. It wasn't worth it to me.

As far as magic goes, I only purchased Freeze Spell. Pivotal. I ditched Holy Guard and Sammoner (well, the last one I bought anyway when I hadn't anything else to spend points on), Sammoner especially with the nerf to its mana cost just isn't worth it anymore. My perks were, in order, Toughness (durability is ESSENTIAL), Student (to get those extra stats), Fast Healer (to compensate for the great damage enemies dished out), Sprinter (I found it impossible to survive the Tank without it), Treasure Hunter for the extra loot in Hell (which was super helpful, some enemies were just pinatas of loot sometimes) and finally Magic Potential when I was about to finish, because Freezing was good. I initially upgraded both Health and Capacity (1 point of Capacity for 2 in Health), then with Student I adapted to the free stuff. 3 STR is necessary for Sprinter, aside from that I got Capacity to 7 or 8 I think and then it was all Life/Spirit (with a predilection for the first of course, I needed to survive first).

It was intense and the lava is still bullshit to me but overall it was great fun, very tense and Warlock is so much better with an harder difficulty setting: it forces you to strategize, rewards your knowledge of the levels and pushes your skill in crowd control and reacting to danger to the limit. I'd keep the one-life thing separate as an additional "special difficulty" though, I know people that would love an Hard mode but haven't the patience to beat THIS hardcore mode if they died on the 4th episode or something.