About This File
Don't leave Imp bodies lying around -- evil spirits will possess them, making the once easily defeated monsters invulnerable to your most powerful attack! It usually only takes about one minute for an evil spirit to locate a dead imp's body and possess it, so it's almost imperative that imp's must be destroyed completely, reduced to nothing more than blood and guts, preventing evil spirits from taking their bodies. I advise using a rocket launcher, berserk fists, or a BFG9000 against the imps. If you see an imp rise from the dead before your very eyes, run from him because once an evil spirit has possessed him, he is invincible.
Humans have something the other enemies don't -- a soul. Killing a sergeant or trooper has serious consequences -- their ghosts will come back to haunt you. Ghosts are able to walk through walls, float through the air, and appear partially invisible to the world of the living. They're much tougher to kill than their former human selves, especially since they're so light; you can shoot one with a shotgun, and he'll fly back into the wall only to re-emerge later when you least expect it. They're fast too -- probably three times faster than they were as humans. And especially watch out for trooper ghosts, as I'm told they have suicidal tendancies.
Here is the patch that brings the undead into your DOOM experience, so load it and try it ... if you think you can handle it!