Play for free - http://darkwalllke.com/Games/Zombie/
Zombie is a free top-down Zombie survival shooter. You can earn cash for killing zombies. Use that cash to buy weapons and traps such as, land-mines, machine guns, rocket launchers, etc. Walk around the town and try and stay alive, see how many waves of zombies you can survive. Using your pistol as well as other weapons and traps, you can kill zombies. Once you have shot a Zombie you'll have to go retrieve the cash left behind. Watch out for traffic on the roads. Speeding cars will kill you, but you can also use them to run over Zombies.