I just saw a lot of stuff in there which looks a hell of a lot like Halo: CE. If that's what I can expect to see in the actual game, I may have a new favourite...
As always, I do have a question.
Is Halo 3: ODST purposefully reminiscent and/or built from/upon elements of Halo: CE? For example: We've got the magnum back, huge open spaces, health packs (I noticed the sound effect of picking one up @ 6:26 is the same too!), no dual-wielding, no BR, etc...
I also noticed a particular part @ ~7:45 in the video which looks extremely similar to a couple of sections of CE too. Eye-spy-with-my-little-eye some Banshee vs. Banshee dogfights too. Yet another possible look back to CE?
: )