Old School informed GURPS Dungeon Fantasy gaming. Basically killing owlbears and taking their stuff, but with 3d6.
You had to show this to me now, didn't you?
Bought it this morning.
Elves and dwarves were once just maggots in the flesh of Ymir! Maybe there are some maggots in dungeon levels that have not transformed into elves and dwarves and they are a new monster for PCs to encounter.