Well done on making your first game-jam game! :)
What I really liked was the idea, art, and music. Really well done in making you game beautiful and sound exciting :)
What I thought could be better is the game loop. While it's fun to fly around in space, I thought the task was too big and repetitive at first.
One way to fix it is maybe to make the ship more easily maneuverable/faster so that it goes quicker, or to simply lower the number of planets to collect from 15 to maybe 3 on the first level. And then add like 3 levels at least for a game-jam entry. And depending on the time you could've maybe even added some variety in difficulty/tasks/obstacles.
Just wanted to give you some things I found could improve the game and what you can take with you to your next project :)
Well done!