Counter-Strike

[Derrick]

Counter-Strike (sometimes differentiated as Counter-Strike 1.6 and shortened to CS) is a tactical first-person shooter video game developed by Valve Corporation which originated from a Half-Life modification by "Gooseman" and Jess "Cliffe" Cliffe. The game has been expanded into a series since its original release, which currently includes Counter-Strike: Condition Zero, Counter-Strike: Source, and Counter-Strike: Global Offensive. Counter-Strike pits a team of counter-terrorists against a team of terrorists in a series of rounds. Each round is won by either completing the mission objective or eliminating the opposing force.

The game was the most played Half-Life modification in terms of players, according to GameSpy in 2008.

As of August 2011, the Counter-Strike franchise (Valve) has sold over 27 million units.

Source: Wikipedia