Returning the series to the Pacific Theater of World War II, World at War—often unofficially referred to as Call of Duty 5— introduces cooperative play for up to four players online on the Xbox 360, PlayStation 3 and PC, in addition to two-player local split-screen cooperative play on home consoles.

The Wii edition of the title also sports what the publisher describes as a "unique" two-player mode, though it was not immediately clear whether the Wii version's co-op mode incorporates online functionality.

Moreover, the publisher added that the cooperative campaign allows players to gain experience points and unlock perks for use in competitive multiplayer modes, similar to the perks system in Infinity Ward's Call of Duty 4: Modern Warfare (PC, PS3, 360). The difficulty of the campaign will scale dynamically based on the ranks of participating players.

"With Call of Duty: World at War, we're re-defining what it means to play a WWII game," said Treyarch studio lead Mark Lamia. "We're excited to give players a host of new enemies that employ entirely new tactics, as well as new, groundbreaking tools—like co-op and the flamethrower—to succeed in the epic fight."

Previously known as Call of Duty 5, Call of Duty: World at War arrives on PC, PlayStation 3, PlayStation 2, Wii, Xbox 360 and Nintendo DS this fall.