An average top-down shooter in a crowded marketplace.
The mechanics are tried and true, survive an endless onslaught of enemies spawning from all corners of the screen; a la Smash TV. Weapons upgrade, enemies become more tenacious, and every second you stay alive pushes you to your inevitable demise. We've seen this before. The only thing is the controls, setting, level design, music, and art design as just boring. That and your character looks like a bootleg Ace Ventura that spouts Duke Nukem lines. It is sad.
If this kind of game is your thing though you might find enough to entertain you enough to get you through an afternoon or so. The weapons, although kind of cheesy have a certain charm to them; like the Groove Gun that makes all of the zombies dance instead of attacking you, or the Brain Sucker that does what the name entails. They are fun but nothing too special.
The only aspect that makes this game intriguing in the least is the "fire system." It is the saving mechanic that allows this game to at least gain some attention. At any point you can push L2 and your character will pull out a torch. Zombies fear the fire so they wont attack you, allowing you to run right through even the largest mass. Doing so though ignites the undead and then the rules change. The zombies will chase you while blazing and trying to attack you. This is a risk/ reward system because a flaming zombie does regular damage and fire damage, and lights any zombie they bump into on fire. Every zombie on fire adds to your score multiplier, so the basic strategy is to run through masses catching them on fire, amassing a train of burning freaks behind you until you are overwhelmed and have to start mowing them down with machine gun blasts.
Overall it might deserve a passing glance for interesting mechanics, but if you need just one shooter on PSN go with Super Stardust HD or Everyday Shooter.