Call of Duty is a first-person shooter set during World War II, developed by Infinity Ward using a modified id Tech 3 engine. The single-player campaign spans three separate perspectives, with the player controlling American, British, and Soviet soldiers across the European theater. Gameplay emphasizes squad-based combat with AI-controlled allies who support the player during missions, making use of authentic period firearms, iron sight aiming, and a health point system with medkits.