Counter-Strike: Source (commonly abbreviated CSS or CS:S) is a PC Game developed by the Valve Corporation. It is a complete remake of Counter-Strike using the Source engine. As in the original, Counter-Strike: Source pits a team of counter-terrorists against a team of Terrorists in a series of rounds. Each round is won either by completing a mission (such as detonating a bomb or rescuing hostages) or by eliminating all members of the opposing team.