Halo 3 Nerdery Ho!
Joystiq’s trailer analysis:
Couple things I’d add. First off, we see two Spartans on screen in one shot. This could simply be an indication of co-op play and not a story element, but as we know there will be different Spartan armour models, and as Bungie tends to have story motivation for things like that, we can speculate that there will be more than one Spartan in the Halo 3 plot. Also, Nadine noticed that there’s a shot of a four-seater Warthog. It has no cannon, just two passenger seats in the back. We speculated this could be handy for the rumoured four-player online co-op.
There’s also this description of part of the first campaign level, although there’s nothing that exciting going on.