Halo 3 - the complete story

Level two:

The story: At the (UNSC) base, you have to hold out and fight the Covenant as part of a guerilla force, giving the Chief the chance to retool and continue on with his trilogy-ending mission.

The evidence: Pieces of concept art show the UNSC base. There's art of the Pelican coming in to airlift the Chief to his next destination. This'll form the end of the third mission and see MC being taken to the dusty plains of Africa. Keen eyes may recognise that as sounding like the dusty plains from the very first announcement trailer.

The gameplay: Level Two should play out in a similar fashion to the start of both previous Halo games. Think Pillar of Autumn and The Armory, i.e. waves of enemies descending on you, on your own turf, as you fight alongside crew and marines fending them off. Expect there to be a ton of weaponry at your disposal too, the chance to get your hands on some of the UNSC vehicles for the first time and the opportunity to experience Halo 3's new driver AI.