Kinda iffy dude.
There're a few minor problems that only a true fanatic (or perfectionist) would care about, but I'll just put them up.
1)Assuming that he was'nt touched throughout the game (bullshit) or only used medpacks and stimpacks before getting the invulnerability artifact, there's no chance in hell that he'd survive a cyberdemon rocket. they deal 178 %, 56% with 200 armour.
2)The boss brain (Aka:Romero) can't spawn Spider Masterminds, Cyberdemons, Arch-viles, or any of the former humans.
Nice music though. I just noticed that I made a funny in #1. anyway, it's ok for a doom movie vocal-less.