Mutant Dungeon VR is a nice little FPS where you walk a dungeon and shoot/kill aliens. The base engine of Mutant Dungeon VR is similar to Wolfenstein. There are doors, keys, first aid kits, ammos, an end button on each maze levels, but there is also radioactive goo close to where you have to wear a radiation suit.
MutantDungeonVR.sit (1.1 MiB / 1.16 MB)
Mutant Dungeon VR for PPC / compressed w/ Stuffit
Architecture: PPC only
Mac OS 8.1 - Mac OS 9.2.2
At least 5.2MB of free RAM
Emulating this? It should run fine under: SheepShaver