Not bad for a game based on co-op play. Not the best, but all in all worth playing.
After I got a friend to help me out, I saw that if we worked together and got into a flanking covered position. We where able to get through most combat without getting hurt too bad, but there where a few areas where that wasn't the easiest route. Again in some of the tighter smaller areas we saw that if we ran up and just bashed there heads in the combat went my faster then trying to stay back and shoot at them. The "Shield" option in some areas was just too darn easy, granted the thing broke sooner or later, but again all you had to do is grab the thing and run up to the enemies while your partner shot anything that moved, in a few cases I was able to shield bash more people then he was able to shoot.
The campaign mode was short and the highest priced weapons (the rail gun and the grenade launchers) were either too inaccurate or didn't have enough ammo. The sniper rifles/rocket launchers were not used enough to need to upgrade them and the fact that you could just redo the first three missions in about 1h30m and get over $50.000 made money way too easy to get. Not just that, but when you beat the game the first time you get all of the main weapons for free! What the hell is the point of endless money if you don't actually need it?
Other then a few let backs and a couple of freezing issues on the PS3, I thought this game was worth the buy, just because it's a good game to play when you just want to shoot the hell out of some people with a partner. I give it a 7.0 because it's not the best shoot 'em up game or the best co-op game, but it's fairly easy and slow paced. Plus it should give you something else to do while you wait for another decent game to come out. Or just give you a small break from COD 4.