Half-Life, often abbreviated as HL or HL1, is a sci-fi first-person shooter computer game developed by Valve Software, first released by Sierra Studios on November 19, 1998. 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 recently graduated theoretical physicist who must fight his way out of an underground research facility whose teleportation experimentations have gone terribly wrong. The game was the first first-person shooter with a story told entirely in-game in real time, without the use of cutscenes. On its release, critics hailed its overall presentation and numerous scripted sequences, and it won over 50 Game of the Year awards in 1998-9. Its gameplay influenced first-person shooters for years to come, and has since been regarded as one of the greatest games of all time.
With over eight million copies sold since, Half-Life is the best-selling PC first-person shooter to date. The Half-Life franchise – expansions such as Half-Life: Opposing Force; standalone Half-Life: Blue Shift; mods such as Counter-Strike, Team Fortress Classic, Deathmatch Classic, Ricochet, and Day of Defeat; and its sequel Half-Life 2 – has seen over 15 million sales.
The game was also released for the PlayStation 2 on November 15, 2001. A Sega Dreamcast port was made, but was cancelled just 2 weeks before release. The fully-playable Dreamcast version has since been released onto the Internet.
The titles of Half-Life and its expansion packs are all named after scientific terms. Half-Life itself is a reference to the half life of a quantity, the amount of time required for the quantity to decay to half of its initial value. Opposing Force is a reference to Newton's third law of motion, while Blue Shift refers to the blue shifting of the frequency of radiation caused by the Doppler effect.