"Call of Duty: World at War is a first-person shooter video game developed by Treyarch and published by Activision for PC, PlayStation 3, Wii, and Xbox 360. It is generally considered to be the fifth mainstream game of the Call of Duty series and returns the setting to World War II, after the storyline of the previous title, Call of Duty 4: Modern Warfare was based in the present day. The game was released in North America on November 11, 2008 and in Europe on November 14, 2008. A Windows Mobile version was also made available by Glu Mobile and different storyline versions for the Nintendo DS and PlayStation 2 were also produced, but remain in the World War II setting. The game is based on an enhanced version of the Call of Duty 4 game engine developed by Infinity Ward with increased development on audio and visual effects. The narrative for the Microsoft Windows, PlayStation 3, Wii, and Xbox 360 versions focuses on the Pacific and Eastern Front theatres of World War II, involving the United States, the Empire of Japan, the Soviet Union, and Nazi Germany. It is told from the perspectives of Marine Raider Private Miller and Red Army soldier Private Dimitri Petrenko and is based on several historical battles. The multiplayer component of the game contains various game modes and a leveling system that allows the player to unlock additional weapons and rewards as they progress, similar to Call of Duty 4. The game also contains downloadable content called "map packs", which can be purchased online. A new feature to the series was the addition of a cooperative mode, which supports up to two players locally and four players online. The game was the second best-selling game for November 2008 in the United States, selling over 1.41 million units. In the UK, it sold twice as many units as Call of Duty 4 in its first week after release, becoming the third fastest-selling video game. It received positive reviews, with praise for its portrayal of the gritty, dark side of war and multiple game modes. However, it was criticized for not building on the success of Call of Duty 4: Modern Warfare. Call of Duty: World at War currently holds an 85% aggregate score on GameRankings and Metacritic." Source: Wikipedia, "Call_of_Duty:_World_at_War," available under the CC-BY-SA License.