Microsoft Corporation entered the video game industry in 2001 with the release of its first home console, the Xbox. Marketed toward serious gamers, the Xbox became known as the top console for first- and third-person shooters, thanks in no small part to one of its launch titles, Halo: Combat Evolved. Combat Evolved became the first game in a huge and lucrative franchise, breaking sales records with more than five million copies purchased by 2005. The game sold with more than 50 percent of Xbox consoles in the first two months of its release, which led it to become known as the Xbox's Killer App, the game that sold the console, as well as Microsoft's flagship series. Developed by Bungie Studios and initially an Xbox exclusive, Gearbox Software and Westlake Interactive released versions for Microsoft Windows and Mac OS X in 2003.
Combat Evolved is a first-person shooter game played in a 3D environment through the eyes of protagonist Master Chief Petty Officer John-117, a cybernetically altered supersoldier from the year 2552. Master Chief is joined by his artificial intelligence (AI) companion Cortana, who resides in the neural interface of the Master Chief's body armor. The plot of the Halo series centers on an interstellar war being fought between humanity and an alien alliance known as the Covenant, complicated by a long history between an ancient intellectual race of Forerunners and a parasitic life form known as the Flood. After crash-landing on the eponymous Halo, a ring-shaped structure built by the Forerunners to destroy the Flood, Master Chief and his crew must rescue any human survivors and get to Halo's control center. Master Chief and Cortana must then attempt to destroy Halo to prevent the accidental spreading of the Flood.
Critics and gamers alike praised Combat Evolved for its strategic elements, its challenging and varied combat, the superiority of the enemy and ally AI, its special effects, and its immersive and visceral soundtrack. Halo's single-player, multi-player, and cooperative options have also been applauded, with split-screens and/or a system link feature allowing several Xbox consoles to be connected via Wi-Fi for up to 16 players. One of Halo's most impressive and well-liked features is its intense combat system. Enemy AI reacts in a variety of ways and the computer utilizes random elements to give gamers different experiences each time they play. Halo players must think quickly and strategically to react to a series of changing goals and hostile situations. Additionally, unlike other first-person shooter games, Halo players can only carry two weapons at a time, which aids in verisimilitude and also forces a player to strategize. The weapons and vehicles in Halo all have unique purposes and drawbacks that can make choosing the correct weapon or transport both difficult and vital to success.
Since its release, Combat Evolved has received 48 awards, including Overall Game of the Year from the Academy of Interactive Arts & Sciences, a non-profit organization of industry professionals. Halo has been extremely significant in the development of contemporary first-person shooter games and its massive fan base, nicknamed Halo Nation, is a tribute to its popularity and influence.
As of 2016, the Halo franchise consists of five core games, five spin-off games, novels, comic books, a live action web series, toys, figurines, evocative soundtracks, and countless pieces of merchandise. The cultural impact of the games is so large that they are being compared to such epics as Star Wars and Virgil's Aeneid.