Woah, this is fun :D Great movement controls, the speed is just right. And the hex shader is absolutely mesmerizing!
I played it until I built a little chaingun fortress that I hid inside, which seemed to make me unkillable. Maybe there should be collision enabled between towers and the player, though that would also require some way of removing them again, otherwise you can trap yourself.
I like how neatly the towers synergize with each other. After a while, I even knew the icons by heart, so the abstract art-style for them was only an issue at the very beginning. Shooting them and then seeing the chain do its thing is really satisfying. Good call on not making them fully automatic!