Halo 3 is a first-person shooter video game developed by Bungie exclusively for the Xbox 360. The game is the third title in the Halo series and concludes the story arc that began in Halo: Combat Evolved and continued in Halo 2. The game was released on September 25, 2007 in Australia, Brazil, India, New Zealand, North America, and Singapore; September 26, 2007 in Europe; and September 27, 2007 in Japan. On the day before its official release, 4.2 million units of Halo 3 were in retail outlets.

Halo 3 s story centers on the interstellar war between 26th century humanity, led by the United Nations Space Command, and a collection of alien races known as the Covenant. The player assumes the role of the Master Chief, a cybernetically-enhanced supersoldier, as he wages war in defense of humanity, assisted by human Marines as well as an allied alien race called Elites, which is led by the Arbiter. The game features vehicles, weapons, and gameplay not present in previous titles of the series, as well as the addition of saved gameplay films, file sharing, and the Forge map editor; a utility which allows the player to perform modifications to levels.

Halo 3 grossed US$300 million in its first week. More than one million people played Halo 3 on Xbox Live in the first twenty hours. As of January 3, 2008, Halo 3 has sold 8.1 million copies, and was the best-selling video game of 2007 in the U.S. Overall, the game was very well-received by critics, with the Forge and multiplayer offerings singled out as strong features; on Game Rankings, Halo 3 ranks as the seventh highest rated Xbox 360 game to date.

Gameplay

The gameplay of Halo 3 builds upon the previous iterations of the franchise; it is a first-person shooter which takes place on foot, but also includes segments focused on vehicular combat. The balance of weapons and objects in the game was adjusted to better adhere to what Bungie Studios Multiplayer Designer Lars Bakken describes as the "Golden Triangle of Halo".Bakken, Lars. "Is Quisnam Protero Damno!" Bungie Studios, 2007. (in English) These are "weapons, grenades, and melee", which are available to a player in most situations. Halo 3 contains the ability to dual-wield, where a player forgoes both grenades and melee attacks in favor of the combined firepower of two weapons simultaneously. Most weapons available in previous installments of the series return with minor cosmetic and power alterations. Unlike previous installments, the player's secondary weapon is visible on their player model; holstered (normally duel-wield weapons) or slung across the player's back. Halo 3 introduces "support weapons", which are exceptionally large, powerful, and cumbersome two-handed weapons which drastically limit the player's normal combat options and slow them significantly, but offer greatly increased firepower in return. In addition to new weapons, the game contains a new class of usable items called Equipment; these items are found in the game world and have various effects and functions, ranging from defensive screens to shield regeneration and flares. Only one piece of equipment can be carried at a time. The game's strong vehicular component has been expanded upon with new drivable and A.I.-only vehicles. Although some vehicles usable in campaign are not available on the default layout of any standard map in multiplayer due to balance concerns.