Yeah, that aspect of the advertising didn't really come through in the game.

I knew we wouldn't see the exact same events as in the commercials, but I liked the Chief running through that city so much. I was hoping for something similar in-game. For that matter, I was disturbed by all those fleeing civilians who were probably about to die - at least eleven colonies were hit, but only seeing it on Meridian didn't really drive home the impact of those catastrophes. Also it's weird that many of the Guardians were directly beneath cities and also why did they bother with those building-crumbling pulses? Shaking the dust off their wings? A show of power?

Poor Grim, expected to answer for an entire franchise :P
Not that I'm posing these questions directly at him - it's just a few things I've been thinking about.