Half-Life: Decay

An American video game developed by Gearbox Software and released by Valve and Sierra Studios in 2001 exclusively for PlayStation 2 as a cooperative expansion for the console version of Half-Life. Unlike other expansions, Decay is designed for co-op gameplay, allowing players to control two scientists — Gina Cross and Colette Green, colleagues of Gordon Freeman working at the Black Mesa Research Facility. Their task is to assist with an experiment that ultimately leads to disaster, opening a portal to another dimension. Throughout the game, players must face alien creatures, military forces, and various puzzles requiring cooperative interaction. In single-player mode, the player can switch between the two characters while the other is controlled by AI. The gameplay remains largely similar to the original Half-Life, but includes unique mechanics for cooperative play. Enthusiasts later ported the game to Windows, making it accessible on PC. Half-Life: Decay received mixed reviews: while praised for its co-op experience and expanded storyline, it was also criticized for its short length and limited platform availability.