Just a couple little details about ODST *Possible Spoilers*

Well as I mentioned in the "Classic" thread, I have a friend who has played it via pirated torrent and modded xbox.
Just a couple specs about the game:

Spoiler

Unlike other Halos, if you beat every level on easy, you cannot go back and play just one level on Legendary. You must unlock every level seperately for every difficulty

Example (I know this isn't the right amount of levels):
Easy: levels 1, 2, 3, 4, 5 beaten, 6 unlocked, 7 and the rest locked
Normal: All levels unlocked
Heroic: Levels 1 and 2 beaten, 3 unlocked, the rest locked.
Legendary: All beaten
You cannot play level 5 on Heroic yet.

This may not be accurate, but this is what the guy who played it said.

Reason this is important it because now you can't ace it all on easy then go back and play the last level on legendary with your friends. You all might have to have the last level unlocked on legendary.

Spoiler

One city, one map, multiple levels.
The city is obviously the same city every time, maybe minor differences like crash sites and debris, but otherwise you play every level in the same general area and have multiple routes, just different objectives etc...