Old School informed GURPS Dungeon Fantasy gaming. Basically killing owlbears and taking their stuff, but with 3d6.
If I already have 3rd ed's Martial Arts and both Compendiums, what could this book add? I might be interested...
It won't add, at all. This is pre-1st edition GURPS combat rules. It has significantly less than 3rd edition, even without the books you mentioned.I just played the heck out of it, and it works just fine as a RPG-ish PvP boardgame.