Gordon Freeman
The original "Half-Life," Valve's first product, was released in 1998 for Windows to critical and commercial success. Players control Gordon Freeman, a scientist who must survive an alien invasion. The innovative scripted sequences were influential on the FPS genre, and the game inspired numerous community-developed mods, including the multiplayer games "Counter-Strike" and "Day of Defeat". "Half-Life" was followed by the expansions ' (1999), ' (2001) and "" (2001), developed by Gearbox Software.