Everything is controlled by left-mouse-click.
Select towers with left mouse
Place towers on the floor and ceiling of the cave with left mouse
Left mouse the ‘upgrade’ and ‘sell’ buttons then select a tower to upgrade and sell towers.
Left mouse ‘Start Wave’ to start a wave.
Action, alien, arcade, attack, cave, defence, defend, future, laser, loot, monster, powerup, sci-fi, shield, Shooting, shotgun, side, tower, treasure