Nice job! You could add an animated shader on the characters to animate them. AI could be an issue as mentioned, it always has issues in contained rooms or corridors. Perhaps if the roof were separate, with no collision it would work.
I'll be honest though, Doom was never my bag and I couldn't really see what the fuss was about at the time. Nice engine, but I was bored very quickly. I felt the same way about the original Wolfenstein 3D. I did like Duke Nukem, as it was more entertaining: Even that, I never really played for long though. Prefer my games to have a plot and some other things to do, other than shoot I guess
The music was great of course!
SPECS: Q6600 CPU. Nvidia 660GTX. 8 Gig Memory. Win 7.
