The retro art is really nice with a pleasing color palette. Everything is detailed enough yet still readable. I think this can be tricky to pull off with a limited color palette, so nice job! Also, did you make the music? It's catchy and fits well with this type of game.
Using the ship to navigate the menu is a cute and fun idea. Really lean into this! Like maybe you can toggle options in a menu by shooting them or something. I feel like you could do a lot of neat things with this menu concept.
I like the variety of enemies and objects to shoot. I also like how they have physics and can bump into each other which makes the game more dynamic.
Encountering the random events is fun. There is a bit of a risk in triggering them since some of them take your health which is an interesting mechanic. Does encountering the bonsai planet do anything?
I would like to see more feedback on your bullets hitting enemies. Some sound effects or having the enemies shake or flash upon being hit. Maybe some particle effects. Something to make hitting enemies more impactful and satisfying.
Overall, nice job. This is a cute game!
If I could make a special planet to vacation on, I picture something like a low gravity water park. I think that would be a lot of fun.