Good Roguelike Games

Monsters simply respawn, even if you didn't leave the level.
Think of them coming from up/downstairs.
After getting used to the race/class and magic system I recommend reading parts of the ADOM Guidebook.
Just skip the chapters of which you think would spoil your gameplay experience too much.

Thanks for that link DerSchcraa it helped alot. I just skim over the major spoilers, but it's helping me understand the mechanics of the game. Especially the healing trait. I'm sorta in a pickle now because I really want a dark elf necro but to get the healing skill I'll have to adjust my alignment towards neutral. I always seem to pick the most difficult way to play a game I guess I'll have to try out alignment shifting with alters. Sounds expensive, but doable.