I'm a little behind on this, but...
Jesus Christ. Is it just me, or was that not the shortest single player campaign experience ever? I think I beat it within 3-4 hours tops, and that's with my conservative first-person shooter style of play.
I hope the multiplayer is interesting, or else I'll be trading this game back in.
There were several instances in which I felt things were too rushed. "Here, jump on a Humvee and shoot this gun! Good, you blew up two vehicles in 20 seconds, now your time in the Humvee is over. Next mission."
While the Goliath was fun to use, it seemed like it was the only vehicle/specialty item that you frequently got to use, aside from the one mission in the helicopter. I also wasn't very impressed with the available choices for weapons, although I guess this is something that will be brought out more in the multiplayer.