Other than the classic Alone in the Dark and Aliens games, there was another surprisingly scary game:
Space Hulk
http://en.wikipedia.org/wiki/Space_Hulk_(video_game)Essentially you remote control several slow but powerfully armed and armoured Space Marines around a derelict Space Vessel which is infested with Alien creatures known as "Genestealers" (and which look like H.R Gigers famous Aliens). There are an infinite amount of Genestealers, but if you can secure points of the map you can cut off their entry points rendering sections of the ship 'safe'.
The reason the game is so bloody scary is because of its controls: It uses the old dungeon style of control system where you can only move in the four cardinal directions, so when you spot a blip coming towards you from 90 degrees it may already be too late. This combined with the incredible slowness of physical attacks they Marines perform means ALL hand-to-hand combat is tense. Especially when the marine being attacked is the only thing standing between the Genestealers and the backs of the rest of the Marines.
Also: Marine guns jam with incredibly unlucky timing.
Marines you are not directly controlling automatically go into 'Overwatch' in which they will shoot anything enemy that appears. Watching in powerless horror as a Marines gun jams and his life light blinks out is a feeling no one should ever be allowed to experience.
