Super solid entry, and a stellar idea! Lots of good work here and a great use of the theme. Forcing the player to get close in order to deal damage was an excellent decision for the core of the fight. Could do with more time to evade attacks since the player is usually so close to the source, but there's a lot of fun in there trying to dodge attacks with tricky orbital movement. Overall I felt my max speed was slow compared to the projectiles, I'd like to be able to dodge them reliably without having to to use the teleport all the time.
The lag spikes are the biggest draw back. When performing evasive burns the frame rate is drops down to slide show levels on my machine. It adds another level of difficulty to what is already a tricky game to get used to. On the topic of difficulty I'd prefer to not lose progress on a game jam style game, and I'd feel encouraged to play riskier if I didn't have to restart from the beginning. Difficulty is ultimately the developers choice though.
Artwork was super cool! Each planet really has a personality of their own. The biggest aesthetic wrinkle is the sound effects, the 8-bit works well but most of the sound effects have a harshness to them. You might want to try balancing their volume out a bit also. Music slaps tho, amazing work!
Fantastic work! With a little polish and optimization this would be a nice prototype. You should be proud, especially for a first game jam submission! Well done :D