Mark Lawson writes: "Bungie claimed that ODST would be an expansion pack for Halo 3; it was to be a 2-3 hour campaign mission. However, the project grew in size and scope as more enthusiasm was taken into the project. Eventually, the game ballooned out into a full retail game. For your money, you get a six-hour campaign with different play style to the Halo franchise and a new cooperative game mode called "Firefight". Then a second disc that gives you the complete Halo 3 multiplayer experience.
You begin as the F.N.G. aka The Rookie, waking up in your drop pod six hours after a disastrous orbital insertion mission to New Mombasa to kill a Covenant cruiser that slips away at the last minute scattering your squad across the city. Your job is to figure out what happened to the rest of your squad and complete a secretive ONI mission."