Gosh there were so many scary parts when playing as a marine! Getting jumped by xenos, seeing blue bolts of plasma from nowhere coming right at you, hearing intense angry sounds and not knowing where they are originating from, crappy building structure coming apart at the seams and scarying the tar out of you every few minutes. Its freaky!
Plus its dark and hard to tell where your enemy is at.
Then you come along and find some skinned bodies hanging from the ceiling, or a body mutilated on the floor. That certainly gets you on edge! Much more than current games, save for FEAR.
But man, youre always on edge, knowing that something can, and often will, come out at any moment from any angle. It was really freaky when youre in the egg chamber, surrounded by dozens of eggs containing facehuggers! Its like walking through a friggen' mine field!
In the first AvP game, I couldnt aim for crap as a marine in the first levels. Id see an alien coming up from a story or two below me, fire a few burts, realize it wasnt working for crap, then pump a few grenades at it, then get shredded!
Oh, and is it just me, or are these older games somewhat more... realistic, than most games today? I mean, playing as a marine makes me act very different from when Im playing something like Call of Duty 4, or Halo. I act like I would in real life! Trouble is, theres no 'crap in your pants' button action for the AvP games.