Counter-Strike: Source - multiplayer team tactical first person shooter developed by Valve Corporation Turtle Rock Studios. This is a remake of Counter-Strike, update 1999 for the game Half-Life. Built on the Source engine game was released in 2004, originally included with Half-Life 2, but later appeared and special , separate edition game. As in the original version of the game, Counter-Strike: Source confront each other counter - terrorist team ( SWAT ) and the team of terrorists in a series of rounds . Each round is won by performing a specific mission (such as undermining the bomb or rescuing hostages ) or after the destruction of all members of the opposing team .