Wow, super ambitious game! I do have to agree with other commenters, it's a bit too difficult! There isn't much room for error for each launch and the rocket controls are a bit challenging, so it's especially hard to succeed if you don't know exactly where you want to go.
I do really like the idea of using the rocket to explore a large world of floating islands. I could imagine a fun metroidvania style game where you can return to islands that have specific challenges when you have more upgrades. To have a more freely usable rocket, you might have to put the platforming sections behind closed doors.
I'm impressed with the amount of art, lighting, and effects you've packed in here! Something about the style is not entirely cohesive for me, it might be that some things are more realistic and others are cartoony? The enemies are fun, I also think they could have been shown earlier in the game. It took me some time to realize that especially for game jams, we shouldn't hold back on showcasing the most unique aspects of our games!