Boy, I have so much to say about this one.
First, I love how the game is kept simple so that the focus and controls are very clear cut to the player - that is a very good game design principle. I found a lot of people mentioning confusing controls for some of the games but this game definitely nailed it on the head when it comes to both visual and gameplay clarity which is very nice.
I think your soundtrack is nice and tame and fits the game well.
And dang, those graphics for the planets look on point (I'm assuming you made all the sprites and if that's the case that's very cool!)
Overall it just looks and feels good to play.
Fantastic Work and Game On!