Great timekiller.
Decent graphics, solid gameplay, and it's a great way to kill some time. Although it gets a bit monotonous after the story, who gives a shit? I get to shoot zombies in the face with goddamn bolts of lightning!
On an unrelated note: The protagonist can shoot fire, bullets, and even lightning from his arm, which he uses to beat the shit out of countless waves of the undead....and you name him Joe. Is that really the ONLY name you could think of? Joe?!