A totally non-linear level, other than needing all three keys to exit, you're free to go anywhere you want. Play on HMP for a Doom-like experience, UV adds the Doom 2 monsters, NTR is real easy. Clear all otherworldly mutants, secure the base, and live to tell another tale.
New level from scratch.
DCK 2.2, BSP 1.2x, RMB 2.1, WinTex 4.0
None that I know of. Nowhere to get stuck, nothing that doesn't work right. Thoroughly beta tested, any mistakes still there are mine alone. This version fixes a problem with getting the red key and a spot where you could get stuck. My apologies to the first couple of hundred Compuserve downloaders and thanks to those who pointed out the error. The mistake happened due to changes made after the beta tests.