I've fought 2 bosses in the same room, and I've heard others talk about facing 3 bosses in the same room, so as Kiya said earlier the dungeons are random. I just wish that the dungeons that had no bosses on the 3rd level would at least have some treasures or something down there. It's just so anticlimactic when you make it to the bottom level of the dungeon, only to find an empty level. IMHO