Amazing aesthetics! Love all the character/set/music assets.
Some things that came up:
1. I wish the player didn't change, b/c I want it to be a journey for me as an alien going through space. When I got to the next level, I was looking for my character, and took me a sec to figure out that the green alien is suddenly myself now.
2. I thought it would be cool since planets can be pushed around, if the player needs to push and get the planet balls into the space portal to get to the next scene.
Good work! :)