Fellow fan blog littleenglishhaloblog put up this wonderful post with screenshots of a Q&A that David Ellis did while on a flight back to Seattle (assumed).
Lots of good info to infer from this:
• There are more loadouts available than shown in the trailer
• The Campaign is playable from start to finish, however 343 will continue to polish it for the next several months
• Grenade impact damage is in
• Button swapping possible?
• Sounds like we may be able to customize the HUD a little. (hiding the center text display-for instance when getting a double kill or assassination) <–I like this idea a lot.
• New playable vehicle…
• Vehicle health has been changed from Reach, no specifics mentioned though
• More weapons not yet shown
• You can replay Spartan Mission in a different way
• There is a reason for the color differences between Prometheans
That’s a lot of good info there. Sure, not too specific, but enough to infer from.