Goblins!

Defend your treasure from the goblin horde! Use your catapult to launch boulders at the enemy to halt their advance. Build defenses such as mines, walls, and magic towers to help defend your kingdom. Each level consists of several attack waves with a build phase in between each, and then an upgrade phase at the end of each level where you can permanently upgrade your catapult and defenses. Build Phase Use gold you've accrued from defeating goblins to enhance your defenses. Strategic placement of buildings will help funnel enemies as well as provide additional attack capability during gameplay. Attack Phase Use the catapult to launch boulders at goblins to take them out. Some defensive buildings also have offensive capabilities to help take down the horde. If the goblins get away with your treasure chests, you lose. Upgrade Phase Apply permanent upgrades to your defenses. Increase your catapult reload speed, blast radius of your mines, etc....