End of the world or not, you don't intend to stay stashed avoiding zombies but rather to kill a maximum of them.
Aboard your mini-tank, try to reach the various garages crushing any undead in your way.
Zombie Tank is a particularly successful clone of "Earn to Die 2012", with many upgrades and a well-calibrated difficulty.
Earn to Die 2012: Part 2
Earn to Die 2012