Hey, you have to make two towers shoot at each other back and forth (a bullet gives more energy than it takes to shoot), the enemies will then get shot in the crossfire when they pass in between. You can also make more than two towers shoot in a circle/loop where they power each other.
So close to getting to the present! Sometimes when you jump on the ramps you fly outside the level and get stuck. All in all a fun game with nice visuals!
Awesome game! Very creative to let the towers power each other. Now that I have figured out how to connect them in loops I think I might have built the perfect defense.