Utilizing the Call of Duty 4: Modern Warfare engine, Call of Duty: World at War throws out the rulebook of war to transform WWII combat through a new enemy, new tactics and an uncensored experience of the climatic battles that gripped a generation. As U.S. Marines and Russian soldiers, players employ new features like cooperative gameplay, and weapons such as the flamethrower in the most chaotic and cinematically intense experience to date. Call of Duty: World at War introduces co-operative play, bringing fresh meaning to the "No One Fights Alone" mantra with up to four-players online for Xbox 360, PS3 and PC, or two-player local split-screen on consoles. For the first time ever players can experience harrowing single-player missions together for greater camaraderie and tactical execution. The co-op campaign allows players to rank up and unlock perks in competitive multiplayer by completing challenges and earning experience points, adding continuous re-playability and team-based gameplay. Whether playing competitively or cooperatively - if players are online with Call of Duty: World at War - they always gain experience points. Based on a player's experience rank and rank of the player's friends, Call of Duty: World at War scales dynamically to provide a deeper level of challenge.