I enjoy both Zombie Shooter and the Dozer. I currently use tier 4 capacitor/tier 4 prototype ammo/tier 4 tungsten armor with the tornado cannon for Shooter. I use tier 4 prototype ammo/tier 3 titanium armor/tier 4 tungsten armor with tornado cannon on Dozer.
I am hooked on Indestructible. Great game, a lot of people online, and it just updated for a single player campaign with a new vehicle free upon completion!