Depends how you play it. I play on hard and I pretend it's real. So I creep around and try to suffer no damage at all.
It's pretty hard to outreact the beasts but it's doom folks. They are amazingly alike in play doom2 and doom3. You know there will be something behind the door. It used to be a sargent on either side just out of sight, now it's a sprite in the door. If you open it carefully from the side, just like in doom2, and crouch (not like in doom2 ;) he won't even see you till you get the first shell into him.
Playing like this induces fear and I love it. 360 checks were standard in doom2 you never knew when something would trigger a beast from behind. I don't know what the monster closet wining is about, the damn base just got demonaicly possesed.
It is doom3 folks and is very true to doom2 and doom.
PenGun