Half-Life is a science fiction first-person shooter computer game developed by Valve Software and the company's debut product. First released by Sierra Studios on November 19, 1998, the game was also released for the PlayStation 2 on November 15, 2001. Valve, set up by former Microsoft employees, had difficulty finding a publisher, with many believing that the game was "too ambitious". Sierra On-Line eventually signed the game after expressing interest in making a 3D action game. The game had its first major public appearance at the 1997 Electronic Entertainment Expo. Designed for PCs running Microsoft Windows, the game uses a heavily modified version of the Quake engine, called GoldSrc.
In Half-Life, players assume the role of Dr. Gordon Freeman, a recent graduate theoretical physicist who must fight his way out of a secret underground research facility (Black Mesa), whose research and experiments into teleportation technology have gone wrong.
On its release, critics hailed its overall presentation and numerous scripted sequences, and it won over 51 Game of the Year awards. Its gameplay influenced first-person shooters for years to come, and it has since been regarded as one of the greatest games of all time. As of November 16, 2004, Half-Life has sold eight million copies. As of July 14, 2006, the Half-Life franchise has sold 16 million units. According to GameSpy, Half-Life is the most played online computer game (excluding MMORPGs), ahead of Half-Life 2.