Half-Life is a science fictionfirst-person shootercomputer game series which consists of two full games and five expansions, as well as a number of demos featuring exclusive content. The series has been ongoing since 1998. Most of the games and expansions in the series have been developed by Valve Software and published by Sierra Studios, although some of the expansions were produced by Gearbox Software. Electronic Arts also took over distribution of the games in the series from Sierra from 2005 onwards. The series was initially released for the PC, but console ports of most installments have also been released.
Half-Life is the first game in the series and follows Gordon Freeman, after he and his team accidentally open a dimensional portal that allows aliens to teleport into the Black Mesa facility. Gordon travels throughout Black Mesa attempting to remedy the situation. Half-Life was released on 19 November1998.
Uplink
Half-Life: Uplink was the official demo to Half-Life (although an OEM demo version entitled Half-Life: Day One was released earlier), featuring a small level cut during Half-Life development. It involves sending a signal to allow access to the Lambda complex. A short five minute film also titled Half-Life: Uplink was produced, but was never released. Uplink was released on 12 February1999.
Opposing Force
Half-Life: Opposing Force
Half-Life: Opposing Force is the first expansion pack for Half-Life, following the role of the "enemy", U.S. Marine Corporal Adrian Shephard. Shephard is assigned to a cover-up operation at the Black Mesa facility, and has to fight previously unseen aliens. Opposing Force was released on 31 October1999 and produced by Gearbox Studios.
Blue Shift
Half-Life: Blue Shift is the second expansion pack, this time featuring Black Mesa security guard Barney Calhoun, who is attempting to escape the alien invasion. Blue Shift was released on 12 June2001.
Decay
Half-Life: Decay is the third and final expansion for Half-Life, only accessible in the PlayStation 2 port of Half-Life. It stars Gordon Freeman's colleagues Dr. Gina Cross and Dr. Colette Green. Unlike previous releases, Decay can be played in co-op mode. Decay is currently being ported to PC by fans of Half-Life. Decay was released as part of the PlayStation 2 version of Half-Life, released on 29 October2001.
Half-Life 2: Episode One is the first of a series of sequels to Half-Life 2, set around City 17 after the events of the original game. It was released on 1 June2006.
Portal is included in the Orange Box with Half-Life 2: Episode Two. A new single-player game, it is set in the Half-Life universe. The player controls a female test subject named Chell as she moves through the Aperture Science Laboratories completing various tests with a device that allows her to create linked portals in physical space.
