Nice game, I really like the aesthetics and the music. Took me a bit to figure out how to build towers: Click the weapon in the menu, then click where you want to place it. A blueprint or change in cursor would've helped here.
After I initially secured my platform the enemies don't really seem to scale up. I would've liked to need a bigger platform to fight against hordes of enemies :) It could also be fun to build a path to other platforms to discover powerups (like new weapons or tower upgrades).
Anyway, I had fun!