Congratulations, you've implemented another genre of game in LD48! I'm not good at tower-defense game and failed to survive too many waves of enemies. I think the game difficulty increasing speed could be slowed down a little bit.
BTW, I can't find any relation between the game and the theme...

I didn't find connection with theme but nice tower defence, like the concept with power points.

The cannons seem not to hit under certain circumstances even if the enemy unit is standing still. And the enemies are spawning in the middle of the base which is a bit confusing.

leak of documentation/tutorial : how to build ? i need some time to find it's by drag and drop.

That was fun!