Overall I had fun with this game. It works beautifully. Some of the background graphics need a little work in making them blend in, but that's pretty much expected in a game jam.
The game is a lot of fun when you're going full speed, dodging planets and bouncing from one gravity well to another, so I'm a little disappointed to lose time for it. If I had one piece of advice for the next game, it would be don't punish players for making use of your best mechanics.
I think what it needs is a reason to play fast and dangerous. Right now, you can just go slow, avoid everything easily, and get home safe and sound, but that's not fun. With a little tweaking this one could be great. You should be proud of it.