The game uses a standard health points system, with a limited amount of health reflected by a health bar. In addition to weapons carried by the player, mounted machine guns and other fixed weapon emplacements are controllable by the player. Call of Duty was one of the early first-person shooters to feature iron sights in game play by pressing the corresponding key the player aims down the gun's actual sights for increased accuracy. Unlike later Call of Duty games, the first allows the player to toggle between different firing modes (single shot or automatic fire). Weapons may be exchanged with those found on the battlefield dropped by dead soldiers. The player has two primary weapon slots, a handgun slot, and can carry up to ten grenades. The player can save and load at any time, rather than the checkpoint system utilized in later Call of Duty games. Each mission features a series of objectives that are marked on the heads-up display's compass the player must complete all objectives to advance to the next mission.

In-game screenshot of Call of Duty on the PCĪs 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. An enhanced port of Call of Duty for the PlayStation 3 and Xbox 360, titled Call of Duty Classic, was released worldwide in November 2009 with the release of Call of Duty: Modern Warfare 2, being available via redemption codes included with the 'Hardened' and 'Prestige' editions of the game. At the same time the N-Gage Version got an Arena Pack with 3 new Levels. In September 2004, an expansion pack called Call of Duty: United Offensive, which was produced by Activision and developed by Gray Matter Interactive and Pi Studios, was released. The game received critical acclaim and won several Game of the Year awards from reviewers. Much of Infinity Ward's development team consisted of members who helped develop Medal of Honor: Allied Assault. This led to a greater emphasis on squad-based play as opposed to the 'lone wolf' approach often portrayed in earlier first-person shooter games.

The game introduced a new take on AI-controlled allies who support the player during missions and react to situational changes during gameplay. Much of its theme and gameplay is similar to the Medal of Honor series however, Call of Duty showcases multiple viewpoints staged in the American, British, and Soviet theaters of World War II. The game simulates infantry and combined arms warfare of World War II using a modified version of the id Tech 3 engine. It is the first installment in the Call of Duty franchise, released on October 29, 2003, for Microsoft Windows. Call of Duty is a 2003 first-person shooter game developed by Infinity Ward and published by Activision.

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