Half-Life (video game)

Half-Life is a first-person shooter game developed by Valve and published by Sierra Studios for Microsoft Windows in 1998. It was Valve's debut product and the first game in the Half-Life series. Players assume the role of Gordon Freeman, a scientist who must escape the Black Mesa Research Facility after it is invaded by aliens. The core gameplay consists of fighting alien and human enemies with a variety of weapons and solving puzzles.

Unlike many other games at the time, the player has almost uninterrupted control of the player character, and the story is told mostly through scripted sequences seen through his eyes. Valve co-founder Gabe Newell said the team aimed to create an immersive world rather than a "shooting gallery". Half-Life was built using GoldSrc, a heavily modified version of the Quake engine, licensed from id Software.

Half-Life received acclaim for its graphics, realistic gameplay, and seamless narrative. It won over 50 PC "Game of the Year" awards and is considered one of the most influential FPS games as well as one of the best video games ever made. By 2008, it had sold over 9 million copies. It was followed by the expansion packs Opposing Force (1999) and Blue Shift (2001), developed by Gearbox Software. It was ported to the PlayStation 2 in 2001, along with another expansion Half-Life: Decay, and to macOS and Linux in 2013. Valve ported Half-Life to its Source engine in 2004, while a third-party remake, Black Mesa, was released in 2020.

Half-Life inspired numerous fan-made mods, some of which became standalone games, such as Counter-Strike, Day of Defeat and Sven Co-op. Half-Life 2 was released in 2004, followed by Half-Life 2: Episode One (2006), Episode Two (2007), and Half-Life: Alyx (2020).