Let's take a moment to discuss what hardcore is and how it applies to this game. The official wiki definition is a mode of playing when you never reload (except for quitting the game or having the game crashed, obviously). In particular, death means restarting the game.

However, especially for the purpose of this wiki, hardcore also, and perhaps foremost, means following difficult self-imposed constraints, the least of which being no-reload. This is particuarly critical to games (or mods) providing a range of difficulties to chose from.

In the spirit of by-gamers-for-gamers, the notion of what is hardcore and what is not shall be left to every player. However, in order to provide consistent content, this page takes the following into consideration

No reload

The essence of PIH. The game natively offers a single-save, permadeath option at character creation called Last Azlanti.

However, in the truest spirit of legendary cRPGs, the game has a fair amount of soft-locking questionable behaviours (or outright bugs). Relying on regular quicksaves and self-imposed no reload may be preferrable in many cases.

No glitch

Major glitches like sequence breaks, chapter skipping, etc, should be abhorrent to hardcore gamers.

On top of this, actions (especially spells) incorrectly implemented should not be abused, or used at all. Common examples are mounted characters getting a full attack after a charge, or "Selective" metamagic applying to spells such as Sirocco.

No cheese

Where to draw the line between cheese & tactical genius is left to you, the player. However, here are a few strong cases for unsanctionable cheese :

Real time mode kiting (you get both full movement and attack, destroying action economy / balance)
Trap stacking, and generally preparing to shotgun an enemy whose appearance is only known through metagaming.
- Possible exception : so-called "optional bosses" are quite clearly designed to be fought fully buffed.
A few builds that clearly designed for cheese, such as
- Thug 1 / Kineticist (unjustifable crowd control)
- Witch of the veil 1 / anything (perma invisibility abuse)
- Anything that has you switching alignment multiple times to stack alignment-restricted features

No (much) rest

As with most fantasy cRPGs, Long Rest after every boo-boo can be a thing, and should not be. Hardcore gamers should (arguably) strive to minimize resting instead, especially when it clearly breaks with immersion (let's sleep in line of the sight of the Balor before we take him on...)

For the record, playing with the above rules on Core difficulty, retaking Drezen (end of Chapter 2) with a single long rest has been done, and without any at all might well be possible.

Only pain

None of the above has any sense, nor would it provide any fun, without a counterweight of high overall difficulty. How much is suitable is left as an exercise to the viewer, as at some point higher difficulty simply do require metagaming.

First-timers may well find "Normal" difficulty to be more than challenging, while experienced players should struggle much below Core.