After releasing RoboBlitz and Psychonauts, Steam digital distribution service will feature another game, better yet, 3 more games.

The end of October will mark the release via Steam of Call of Duty, Call of Duty 2 and Call of Duty: United Offensive and Gun. This release is a result of a contract signed between Activision and Valve Software. Activision representatives stated that the decision to sign this distribution contract was taken because they wish to reach a wide range of customers and they can do so by tapping in to Steam's 10 million users' base.

Call of Duty is a game similar to Medal of Honor: Allied Assault when it comes to theme and gameplay. What is different about COD is that players are not embodied only by a US soldier, but by British, Soviet and American soldiers.

The game also features several multiplayer modes like Deathmatch, Behind Enemy Lines, Team Deathmatch, Retrieval, and Headquarters which was added later on with the 1.2 patch. The first installment of the COD series was developed based on the Quake III engine.

Three years after the first version of Call of Duty was released, back in 2003, by Activision, Steam managed to grab the game along with its sequels.