Halo: Combat Evolved Anniversary and the original, Halo: Combat Evolved, are identical in gameplay and plot.[2] The game is a first-person shooter with portions of vehicular combat taking place from a third-person perspective. The plot follows the player character and protagonist Master Chief, a supersoldier, as he fights the alien Covenant on the mysterious ancient ringworld Halo.[2] Players are equipped with a recharging energy shield that absorbs damage; players also have health that can only be replenished by health packs scattered across the game's levels. A variety of human and alien weapons and vehicles can be used.[3]
Players can switch between the "classic" graphics of the original game and new graphics developed for the remake by pressing the Back button on the controller.[4][5] The classic and new graphics are presented in high-definition, 16:9 widescreen compared to the original game's 480i resolution and 4:3 aspect ratio.[6] The remastered graphics are also available in stereoscopic 3D for compatible televisions.[7]
Additions to the gameplay include Xbox Live achievements, online cooperative gameplay, and hidden content: video terminals that provide additional plot information, and collectible skulls that modify gameplay when activated.[2] Support for Xbox Kinect includes voice commands for video navigation, in-combat directives, and environment-scanning, which adds on-screen items to an encyclopedia called the Library.[2][8][9]
The original Combat Evolved did not support online multiplayer, but players could play multiplayer locally via split-screen or System Link LAN.[10] Anniversary adds revamped multiplayer and two-player co-op campaign support available both online via Xbox Live and offline locally.[2] The game's multiplayer mode uses Halo: Reach's engine and features seven remakes of Combat Evolved and Halo 2 maps.[2] Anniversary also includes a new map based on Halo's eponymous campaign level for Firefight, a wave-based survival multiplayer game type in which players and their allies fight enemy groups of scaling difficulty.[11] Anniversary introduced artificially intelligent Firefight allies to the series.[11]
