http://store.steampowered.com/app/39800/Basically, it's a third person top down viewing zombie shooter in which you can gain levels/bonus perks for every level and shoot at zombies with a variety of guns.
It's cheap and doesn't need a godly computer to run it.
It's $6.99 as of now, but I suggest you play the demo first and try it out.
It seems a little hard at first but eventually you'll grasp the concept.
