The zombies had to came up with a new method to zombify humans now that the humans fortified theirselves inside big walls. Launch the zombies with a big catapult over the wall and watch the zombie mayem unfold.
Use the mouse cursor to aim and shoot a zombie. Buy upgrades and evil gadgets with your points inside the evil lab. Click on the 4 zombie buttons at the bottom to use attachable items (must be purchased from item shop first).