When playing as the Alien, the player's objective is to rescue the Alien queen, who is being held captive on a Predator spaceship. The player must fight numerous marines and Predators through various sublevels of the ship in order to reach the Queen. The Alien is unable to heal itself from injuries and instead "cocoons" marines; if the Alien dies, a previously cocooned marine will spawn a new Alien, allowing the player to continue from that location. The Alien is unable to use elevators and instead travels between levels of the ship through air ducts.