Alien is a 1984 video game published by Argus Press Software Ltd. for the Commodore 64, ZX Spectrum and Amstrad CPC (the Amstrad version was released in 1985).
The entire game takes place aboard the Nostromo, which is viewed from a top-down perspective displaying the layout of the vessel. At the beginning of each game the entire crew is alive, and one of them is randomly selected as the one carrying the Alien. The Alien will be born shortly after the beginning of the game, killing the crewmember. After this, the alien hides away, quickly matures and begins to wander the ship, trying to kill the remaining crew. The goal of the game is to kill the Alien.
To this end, any remaining crew members may be controlled by the player. It is possible to attack and kill the Alien directly using various weapons around the ship. Another alternative is to set the ship to self-destruct with the Alien on board and escape in the shuttle, though as in the movie, the entire crew cannot fit in there. Also at the beginning of each game it is randomly decided which crewmember is the synthetic and will eventually try to aid the Alien. If the player can figure out which one it is, this can be prevented by placing him or her in cryosleep before the player loses control of the crew member. At the end of the game the player is given a percentage score which is based on several factors including how many crewmembers are alive, whether the Nostromo self-destructed and if the player successfully identified and contained the synthetic crew member.