Yeah this seems pretty similar to the Halo 2 advertising campaign in 2003 - 2004. First they released that insane teaser (like you said Darkblade) of the MC -with sick graphics- jumping out of that ship into an atmospheric space battle over earth. Then at E3 2004 we got that crazy live demonstration of New Mombasa, once again in sick graphics. AI was insane, and gameplay elements looked too good to be true.
But then the game was released in late 2004, and almost none of what had been seen in ANY of the trailers had made it into the game. There was no triple melee, no single shot BR w/scope, the battles were small-scale and linear, and the cutscenes were really any good. No pre-loading of cutscenes (to alleviate loading times) meant that the cutscenes were glitchy and crappy looking, with all the textures randomly shifting everywhere. Sure Halo 2 MP rocked, but there just didn't seem to be a real impressive SP (which there was in Halo CE).
All Bungie really has to do in order to make a great game is make a game better then Halo 2. Given that they removed so many elements from Halo 2 because they Xbox wasn't 'powerful enough', then they should (touch wood) have a field day with the 360 power. It will be interesting to say the least 😀
I agree with you though big_dogg85, they seem to be creating the same level of hype as the last Halo game. Hopefully they don't make the mistake of seriously overhyping the game!