Should you decide to play as the human space marine, you will quickly find out why I claim for this to be one of the scariest PC games of all time. Everything pretty much kills you really fast. You have the worst vision in the game (the game is pretty dark enough as it is) and you have to rely between switching your night vision off and using your motion sensor which has the same sound effects sort of like the second Alien movie, Aliens. Your weapons range from the assault rifle to a smart gun, various rocket/missile launchers (overkill usually, and can kill you from the splash damage) to the flame thrower. You will get nervous playing as the space marine as you hear the claws and feet of multiple aliens coming at you from every direction.