Counter-Strike (CS) is a multiplayer first-person shooter video game that takes place in modern time. It was released November 1st, 2000 for the computer, published by Sierra Entertainment and developed by Valve Corporation. It was the creation of a new series, the Counter-Strike series. Since the creation of the series, many games have been created such as Counter-Strike: Condition Zero, Counter-Strike: Source and Counter-Strike: Global Offensive.

The game started as a Half-Life mod, created on the brand new Goldsource engine. Both the mod and the game shared nearly the same attributes, they were both fast-paced team-oriented games. The original Counter-Strike did not include any single-player campaigns or computer-controlled players. Although, several server-side modifications added bots. Counter-Strike was the most popular Half-Life mod for many years and still is one of the most popular PC games. Since its release, Counter-Strike has sold over 4.2 million copies, more than any other Valve game besides Half-Life and Half-Life 2.