Just a really well designed little game!
Enjoyment: I found the game easy to pick up and understand. Having the player level up to unlock new elements for the build was really effective at keeping me engaged and I genuinely kept replaying to see how much further I could get if I optimized my build.
Creativity: I think creatively the game is a nice twist on this genre of defend from swarm games. I like how you integrated the theme, i think changing the scale of gravity and by extension your range was a cool way to do it. I also like that you can scale the size of the moon, and that it is actually a major component in optimizing the moon because if its big and it blocks bullets then it becomes waaaay more useful. (very nice synergy! but now I have appeared to wander back into enjoyment talk.)
Style: The game is just so pretty and cute. Everything that should provide visual feedback does and most of the enemy designs are effective and clear. In general the game is just very readable. My one piece of feedback in this area is that I think the small drill enemies are the hardest to see because they are small and share a similar color palette to the background.
All in all, I had a ton of fun. Well done.