Chasm: The Rift. I originally played the shareware version of this several years ago, and I liked it a lot. I'm also a fan of Quake, and although I prefer Quake, I still think Chasm was a good game. I didn't get the full version until many years later. I played through the game and enjoyed the levels, enemies, and especially the bosses. Even for being the "Poor Man's Quake", this is a classic game that I still like and haven't forgotten.