Counter-Strike:Source (CS:S) is a team based first-person shooter, which is an upgraded version of the original Counter-Strike mod for Half-Life using the Source engine that was used in Half-Life 2. The game was originally a total conversion mod made in the GoldSrc engine. All the Counter-Strike games pit a team of counter-terrorists against a team of terrorists in rounds of competition won by completing an objective or eliminating the opposing team. A more in-depth explanation on the rules and gameplay of CS:S can be found on the Counter-Strike page.
Counter Strike Source Portable Works Online
