Call of Duty is similar in theme and gameplay to Medal of Honor, as it is made out of single-player campaigns and missions. In September 2004, it was accompanied in by an expansion pack named Call of Duty: United Offensive, which was produced by Activision, and developed by Gray Matter Interactive Studios, with contributions from Pi Studios. The game is based on the Quake III: Team Arena game engine.

It is the first installment in the Call of Duty series, but was not as widely distributed until the release of the game Call of Duty: Classic for the Xbox 360 and the PlayStation 3, remastered in high definition. It was released on October 29, 2003, for the PC, published by Activision and developed by Infinity Ward. Keyboard and mouse ' In war, no one fights alone.' - Game sloganĬall of Duty is a first-person shooter video game that takes place during the events of World War II.