: The two Halo 2 trailers I can recall showed the Master chief in a situation
: very similar to the one that ends the first level of Halo 2 (jumping off
: the Cairo), and the runthroughs Jamie was doing at E32K3 on Earth ("I
: didn't think they'd send a Spartan"). Both of those fit directly
: (with very slight differences) into the beginning of the story of Halo 2.
: Are you thinking of a different announcement trailer than I am?
I think the complaint most people have is that in the trailer, the Covenant seemed to have a much bigger fleet attacking Earth. "The entire fleet is engaged" and so on. In the final version, it never seemed like Earth was really in danger of losing.
Also, I didn't notice anything in the final game about the Chief having to board and take over a Covenant ship singlehandedly; or humans deploying gigaton bombs on their own soil in a futile effort to stop the invasion.