It's fun, just flawed. It's not really just a side-scroller because there is some depth to your movement, but the main complaint is that while you can move freely, you can only hit things on a straight line. But enemies can hit you from wherever. Level progression is decent but unremarkable. Graphics are okay. Story, who cares. Survival elements are not obnoxious, which I like. Brain off, shoot some zombies. Won't wow you, but worth a few hours at least.