Quote:Half-Life 2 (stylized as H?LF-LIFE2), the sequel to Half-Life, is a first-person shooter video game and part of the Half-Life series. Developed by Valve Corporation, it was initially released on November 16, 2004, following a protracted five-year,[8] $40 million development cycle,[9] during which a substantial part of the project was leaked and distributed on the Internet.[10]

The game was developed alongside Valve's Steam software. It introduced the Source game engine and, because of Steam, was the first single-player video game to require online product activation.[11][12]

Like its predecessor, Half-Life 2 was met with critical acclaim.[13][14] It was praised for its advanced physics, animation, sound, AI, graphics, and narrative. The game won 39 "Game of the Year" awards[15] and the title of "Game Of The Decade" at the 2012 Spike Video Game Awards.[16][17][18][19] Over 6.5 million copies of Half-Life 2 were sold at retail by December 3, 2008,[20] (not including the number of sales via Steam).[21] As of February 9, 2011, Half-Life 2 has sold over 12 million copies.[22]