In many ways, Project Validus is the ultimate overhead zombie shooter. Like many other similar games with overhead city views, you must move through the streets collecting ammo and killing zombies while leveling up. Somehow, Project Validus steps this up a notch with smoother gameplay and VERY aggressive zombies. While I wouldn't mind if the zombies were a little SLOWER, you can soon increase your speed to give yourself a break.
Project Validus also features 3 soundtracks, and the level up system isn't so complicated or time consuming that it takes away from the gameplay. Great zombie game!