Tower Siege
In Tower Siege, build a tower from the blocks you are dealt and defend it from wave to wave. Between attacks you receive a hand of four shapes, including walls, archers, cannons, mortars, and tesla coils. You get a short window to place them before the enemies arrive.
The horde includes goblins, boar-beasts, burning hounds, bone knights, and siege engines that can hit farther than your units. Unsupported blocks fall, and the rubble can crush what is below. Spend wood, stone, and gold, unlock the tech tree, and see how deep you can get.