Discover more about the build-up to the classic Halo 3

ODST stands for Orbital Drop Shock Troopers

You no longer play as the indestructible Master Chief

Sgt Johnson is available as a pre-order bonus character

You no longer play as a Spartan super soldier, but as a sort of futuristic paratrooper with less high tech armour and abilities. Much of the game is told in flashback, as you search for your missing teammates in New Mombasa and discover more of the backstory of the Halo universe.

Of course this being Halo the multiplayer is just as important as the story campaign, with the basic modes being identical to Halo 3 and using all 24 current maps. New mode Firefight though is a four player co-op mode similar to Gears of War 2's Horde - perfect for Halo fans looking for more action.

• Semi-super soldier: Get used to a dirty, more tactical style of warfare as you join the elite ODST in a story set two weeks prior to the events of Halo 3.
• Halo world: For the first time ever in a Halo game you can explore an open world environment, with the freedom to go anywhere and use any vehicle.
• Classic action: Fight in the revamped multiplayer mode from Halo 3, with access to all 24 maps released so far, including all downloadable map packs.
• War without end: New Firefight multiplayer modes introduces four play co-operative action against an unending wave of Covenant forces.