I sort of like how ChAoS is, well, able to mess up your game in more than a single sort of way. I also like (from a theoretical point of view) how ADOM is possibly unfair in every way possible. I love how the player and his character can be totally owned by blind and stupid fate and that there is no inbuilt 'right to win when played well' for every character. This is what makes ADOM different from the standard 'create a character and slash your way through hordes of monsters'-game; these generally are very obviously designed to make it slightly difficult for you, but with a little bit of analysis and practice every problem can be overcome quickly (and you can save/load forever until you fiddle out the right strategy). These games and worlds are designed to be beaten, which doesn't make much sense from an 'inner-game' point of view. ADOM does cater much less to the players needs and mindset. It's not cut in appropriately-sized pieces and problems, nor is it warning you in capitals that you are about to die. It does not protect you from early demise by bad luck with traps, nor does it forbid rivers to cut off your path towards the healing skill. You can be incredibly lucky with early altars and precrowning with Vanquisher while quickly dying to an invisible Ogre Magus on the next level.
When being/playing that character this experience can be painful and senseless and conflicts with our idea that a game should be made to be beaten; that a player, by buying or downloading it, has a 'right' to a fair chance to beat the game. But the absence of such notions is the core of ADOM life; better luck next time and there's no money back either! ADOM-players need to learn quickly that the game is not built to comfort and encourage them; beating this game has much to do with developing your own mindset and abilities. Inability to change your way of thinking 'what a game should be like' makes you quit it quickly.