Your aim in this zombie defense game is to protect you home from hordes of zombies. Use YOUR MOUSE to aim and click LEFT MOUSE BUTTON to shoot. If you have grenades, then hold the SPACEBAR to aim and click the LEFT MOUSE BUTTON to throw. Click on ammo pile next to your character to reload one bullet into the rifle. You can upgrade your weapon and grenade capacity and power during the game. You can buy defensive barricades in the scroll box at the upgrade menu. These barricades will degrade to nothing if zombies destroy them. Some are stronger then others. When ammo power is fully upgraded, a single bullet can penetrate 2 zombies at once.