Counter-Strike is a modification (MOD) to the excellent game, Half-Life. It modifies the multiplayer aspects of Half-Life to bring to it a more team-oriented gameplay. Counter-Strike provides the player with an experience that a trained counter-terrorist unit or terrorist unit experiences.
The MOD is team-based featuring one team playing the role of the terrorist and the other team playing the role of the counter-terrorist. Each side has access to different guns and equipment, as well as different abilities. Maps have different goals such as: hostage rescue, assassination, bomb defusion, Terrorist escape, etc.