Halo 3 is the third game in the main Halo series. Like the rest of the series, it is a sci-fi/military-themed first-person shooter with an emphasis on vehicles and an extensive multiplayer mode in addition to the single-player campaign.

As before, the series' signature shield system is used where, rather than health, you have a force field of sorts which loses power as you are attacked. You needn't pick up anything to refill it, only take cover for several seconds. If you can avoid being attacked, the shield will recharge on its own.

Vehicles are again present. These are human and alien transport which can be driven or ridden in with another player or AI doing the driving. Halo 3 adds numerous new types of vehicles, notably a massive mobile command center called the Elephant and a human VTOL aircraft called the Hornet. Enemies with good timing can board a vehicle, kicking out the occupant.