Robinson's Requiem and Deus are survival games at their core, and they are even more brutal than many roguelikes. That is saying a hell of a lot.
I was quite impressed by the complexity of the world not to mention the attention to detail. Never before was your character able to contract all kinds of diseases and ailments.
The only game that allows a person to cut off all of their limbs! How could you not buy a game with a feature that awesome ;)