Call of Duty 1 Walkthrough of the Single Player Campaign played on PC without commentary! Call of Duty is a first-person shooter video game developed by Infinity Ward and published by Activision. It is the first installment in the Call of Duty franchise, released on October 29, 2003, for Microsoft Windows. The game simulates infantry and combined arms warfare of World War II using a modified version of the id Tech 3 engine. Much of its theme and gameplay is similar to the Medal of Honor series; however, Call of Duty showcases multiple viewpoints staged in the British, American, and Soviet theaters of World War II. As a first-person shooter, Call of Duty places the player in control of an infantry soldier who makes use of various authentic World War II firearms in combat. Each mission features a series of objectives which are marked on the heads-up display's compass; the player must complete all objectives to advance to the next mission. The player can save and load at any time, rather than the checkpoint system utilized in later Call of Duty games.