Old School informed GURPS Dungeon Fantasy gaming. Basically killing owlbears and taking their stuff, but with 3d6.
I have to go to a meeting for work, but I quickly perused DF22: Gates. Very cool.
The game will be more fun for you if you don't read the sample gates. One of them does have Felltower spoilers you're unaware of, yet.
Ah, good to know. Glad I only got it a few minutes before my meeting and only skimmed it.