Co-Op Campaign: Treyarch elevates the Call of Duty social gaming experience by delivering a campaign with the ability to play cooperatively with up to four players online, using the same battle-tested network infrastructure and social systems that support its world-class Multiplayer and Zombies game modes. Cinematic Arena-Style Play: Designed for co-op and re-playability, players encounter all the epic cinematic gameplay moments Call of Duty is known for delivering as well as new open-area arena-style gameplay elements designed to allow players to approach the game with a different strategy each time they play.