well at least for the parts i have played... i'll update once i upgrade to Gold Membership again to play multi player.
Story So Far:
In the beginning you'll get a little info about whats going on. Then few moments later you'll meet, what i believe, are the main characters. After they do some talking you'll get ready to drop into battle. And this is where you start playing. I'm not gonna say anymore but i will say that you will learn about what is happening very soon in the game.
Review:
They story is great and accurate to what I thought was gonna happen. You'll be able to play more then one character. Its kinda like Halo 3 but a little more difficult due to the lack of energy shields. Has a lot of action and BIG maps. You can get lost, but you can find different things while you are trying to find your way back on course. Instead of having an A.I. like Cortana, you will be helped by the "City" itself. And in this game you can choose different paths, instead of one line.
Pros:
FUN!
Easy achievements
Comes with a Halo 3 style multi player Disc that has all 24. You don't need Halo 3 to play this.
Multiple Characters
Cons:
Harder to survive.
Only 2 new weapons (silenced SMG and SOCOM pistol)
OVERALL: 10/10