Into Uncharted territory... again.
The multiplayer is fun, however, it seems slightly tacked on. It is so immersive though, so you probably won't notice. It is a good time waster, but it isn't Team Fortress.
The game is overall fun and exciting, and the treasures will have you doing the campaign over and over. Heck, you may just play the campaign because it is so fun. The only thing that keeps this from a ten is the fact that it doesn't do anything "new", other than the impressive set pieces. It is a game worth visiting and replaying multiple times, and each time is just as fun as the last.