Great high-quality graphics, but the in-game UI should definitely pop out more. If I understood it correctly, your health is the resources you use for building? Anyways, in a game where you have health, it should be conveyed very clearly - here it was the neon blue color that blended all too well into the other graphics.
The enemies seemed interesting, but there was something about the movement that made them odd. Perhaps the flying enemies got stuck too much and I had to go out and bait them, and the kamikaze enemies felt unfair and unavoidable due to the platform setup (not much space to jump and avoid them).
I think there was just way too much visual clutter from the start - adding a tower to a platform didn't suddenly make it a super-powerful thing visually, and they all just blended into the platform structures themselves. Enemies and projectiles were visually contrasted, that was good.
Sound effects became very monotonous quickly, and the enemies' laser attack sound was distorted and snappy, irritating even. The background music was really good though, fell right into place with the visual theme.
The builder's movement was weird, he glided along the platforms a lot, and the jetpack length felt too short. A few times I fell off the edge and tried to jetpack but couldn't.
I guess I had very high expectations of the gameplay after seeing the menu and the story screens, the mood of the game was built well together even though I skipped all the story text.