Halo 2 is a first-person shooter video game developed by Bungie Studios. Released for the Xbox video game console on November 9, 2004, the game is the second video game title in the Halo franchise and the sequel to 2001's critically-acclaimed Halo: Combat Evolved. A Windows Vista version of the game was released on May 17, 2007, developed by an internal team at Microsoft Game Studios referred to as "Hired Gun". The game features a new game engine, as well as using the Havok physics engine; added weapons and vehicles, and new multiplayer maps. The player alternatively assumes the roles of the human Master Chief and alien the Arbiter in a 26th century conflict between the human UNSC and genocidal Covenant. Players fight enemies on foot, or with a collection of alien and human vehicles.

After its initial release, Halo 2 was the most popular video game on Xbox Live, holding that rank until the release of Gears of War for the Xbox 360 nearly two years later. By June 20, 2006, more than 500 million games of Halo 2 had been played and more than 710 million hours have been spent playing it on Xbox Live; by May 9, 2007, this number had risen to more than five million unique players on Xbox Live As of November 2008, Halo 2 is the best-selling first-generation Xbox game with 8.46 million copies sold worldwide, with at least 6.3 million copies sold in the US alone. Critical reception of the game was generally positive, with most publications lauding the strong multiplayer component; at the same time, the campaign was the focus of criticism for its cliffhanger ending.

Gameplay

Certain weapons can be dual-wielded, which allows the player to trade accuracy and the ability to use grenades and melee for raw firepower. The player can carry two weapons at a time (or three if dual-wielding; one weapon remains holstered), with each weapon having advantages and disadvantages in different combat situations. For example, most Covenant weapons eschew disposable ammo clips for a contained battery, which cannot be replaced if depleted. However, these weapons can overheat if fired continuously for prolonged periods. Human weapons are less effective at penetrating shields and require reloading, but cannot overheat due to prolonged fire. The player can carry a total of eight grenades to dislodge and disrupt enemies. A new ability found in Halo 2 is the ability to board enemy vehicles that are near the player and traveling at low speeds. The player or AI latches onto the vehicle and forcibly ejects the other driver from the vehicle.