With the World at War, Infinity Ward's veteran military first-person shooter series heeds a call to return to its WWII roots. Built on the Call of Duty 4 game engine, World at War aims to bring Modern Warfare's state-of-the-art graphics, interactive battlefield environments, unflinching "M"-rated presentation, and sophisticated online multiplayer options back to the World War II setting in which the series earned its stripes. As (at least) the fourth original console and home computer Call of Duty title set during World War II, World at War offers an expanded selection of era-authentic infantry and vehicle weapons, as well as the tactics that go with them, such as using flamethrowers to burn away camouflaging cover and expose hidden enemies. For the first time in the series, co-operative multiplayer gaming is strongly supported, with team-up options for two players to play through the main campaign in split-screen mode, or for as many as four to play together online. Call of Duty: World at War is set in the Pacific Theater and in Europe, near the end of the war. In the single-player campaigns, players take the role of a United States Marine or a Russian infantry soldier, and face an onslaught of deadly new techniques, including brutal guerrilla warfare and kamikaze attacks. In online multiplayer games, an increased emphasis on squad tactics in chaotic, bombed-out environments makes coordinated teamwork the deadliest weapon of all.