Aliens versus Predator, often referred to as AVP1 by fans (despite not technically being the first game in the series), is a 1999 science fiction first-person video game developed by Rebellion and published by Fox Interactive for the PC and Mac. An unofficial port to Linux was later released in 2001, following Rebellion's public release of the game's source code. The game features three separate storylines for each of the playable factions, the Aliens, the Predators and the Colonial Marines; while each plot is unconnected, the Marine story loosely follows on from events of Alien and Aliens, while the Predator plot includes elements taken from Alien3.