oh yeah, picked this shit up yesterday!
I'm not very far (haven't even gotten the sweet helmet yet) but I've been having a blast and the shooting isn't actually that bad once you upgrade your guns a little bit. My machine gun shoots exploding bullets now, so it doesn't take nearly as long to kill things as it did in the demo. Oh also, that demo level is way better in the actual game. That floating white building on top of the blue energy pillar, for example. You have to go inside of it to shut the shields off and when you do, it falls out of the sky so you have to basejump through the thing, dodging pillars and beams and lasers on the way out. It's like it was ripped straight from the rulebook for making action movies....except you actually have to do it yourself.
What else...oh the vertical cover thing! Not sure why they left it out of the demo completely but it's pretty sweet. It's intuitive and easy to use, and timing your grenade throws so as to not blow yourself up is pretty satisfying. Beyond that, it's pretty much just like fighting on the ground except you occasionally have to hammer on a random button to keep your "grip" and prevent yourself from falling off if an explosion goes off near you or something.
The graphics are actually pretty good (besides the faces, oh god the faces). There colors are a little extra saturated and there's lots of lens flare and heavenly-looking bright white light, so it looks very pretty and impressive even if it technically isn't.
Also, there was apparently a pre-order bonus that I didn't know about that gives you a golden jetpack that's pretty baller. Speaking of which, I bought it for ps3 but they gave me an extra code to redeem for the jetpack...for 360(?). So if anyone's playing this on 360 and didn't preorder, I have an extra gold jetpack code that's available.