Zombie Cannon Shot

A huge wave of zombies is coming. We just have a mount fortress to stop them. What you need to do is to control the shots to hit horrible zombies.

Gameplay:
--Use your finger to drag on screen. Control the strength and adjust the angle according to the guideline to shoot.
--High scores and shells can be got when zombies are constantly hit.
--Don't hit any obstacles, otherwise you will waste your shells.
--Something like "double kill" "triple kill" may occur when you hit oil tank.