The player has two primary weapon slots, a handgun slot, and can carry up to ten grenades. Weapons may be exchanged with those found on the battlefield dropped by dead soldiers. Unlike later "Call of Duty" games, the first allows the player to toggle between different firing modes (single shot or automatic fire). "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. In addition to weapons carried by the player, mounted machine guns and other fixed weapon emplacements are controllable by the player.