Zombie Battle field

The world now belongs to the zombies.  The few surviving survivors are scattered everywhere.  Some are in the Fort, where there are heavy guns that keep the undead in.  Fortunately, you are in the Fort and it is your job to keep it away from the undead   The game is played via mouse.  The idea here is to kill zombies right way after you spotted them. You will need to kill the entire zombies to proceed to the next level.  Afterwards, you will earn money and you can use that money to buy better guns and hire some soldiers to help you defend the wall.