Very cool entry!
I think the gameplay works really well, the controls are very challenging but don't feel unfair. The floatiness of the spaceship feels very spacey and appropriate! I always felt a bit tense playing it since I didn't want to crash, but I think for people who want to speedrun this they'll probably be able to figure out ways of controlling the spaceship very tightly while going at full speed. I feel like there's enough depth for speedrun techniques to be developed, which is nice. It might be good to offer some more tech for speedrunners tho - things like tight shortcuts and stuff like that. Maybe there could also be some sort of tradeoff between overheating and speed, since right now the overheating seems like it's purely a downside. Maybe you could play around with having a zone before you're overheating, something like an "optimal temperature", that makes you go faster in some way or something. Just some ideas!
In terms of the theme, I think it was very well implemented and ties in to your mechanics and presentation, which is very cool to see. It feels like this game was created specifically for this theme, which is great!
Your aesthetics are great. All the sprite work is very pretty, and all the bloom-y particle effects look amazing. The visual presentation is very well done, and I like it a lot.
In terms of sound, I think your music right now is very cool and very clubby. If that was me, I think I'd try to add in a bit more space color in there! Right now I feel like it really plays into the speed element of your game and it's definitely exciting, but it'd be really cool if you managed to keep that while also tying it a bit more into the space theme you've chosen.
Very cool entry, keep up the good work! :)