I've had it for a few days now and for what it is, it's great fun.
I'm a massive zombie movie fan so getting this game was a no brainer for me.
I've had some sensational online fun with it. Wait till late at night, all the lights off, and preferably a few drinks and its made me jump out of my skin a few times. I had a great group of guys the other night who were keen to role play it and man that was fun. Especially as we all just randomly happened to be intoxicated, so we pretended we were just a bunch of drunk dudes fighting zombies, so funny. This one American guy had the rest of us laughing so hard we had to keep muting the mic's. (according to a drunk guy from Texas, I talk funny hehe)
From a gamers point of view it lacks polish, especially after the graphical orgy that Gears 2 is, but at the end of the day I give mad props to the developers for making a game for Zombie Movie Lovers. It's a risk financially to target a game so specifically, and then to all but abandon single player and the requisite storyline, but they did it, and after a tough day, there's stress to be relieved in blowing up zombies I gotta tell ya.