Thank you for taking the time to play and leave a review! You're right about the graphics- there's no defense there.

I am curious what you mean by spongy controls, as that's something I'd like to learn to improve on. I uploaded a new version today where releasing the jump key causes you to stop ascending (unless you're bouncing off an item block or rocket jumping) that might help the game feel more controlled, although I think it makes the game a little harder as you may accidentally lose height while double jumping.