Atmosphere was great between the sound design and the lighting. It was fairly easy to tell that the dark, barely-visible cubes were not enemies and the reddish, bright, animated pac-man planets were the enemies. The cutscenes were pretty cool too.
The boost felt great. Flying around the game was fun. The trail changing size gave you a great indicator of how fast you were going. The speeds felt just right. Unboosted, the enemies caught up to you and then boosting got you out of danger quickly. The cooldown was the perfect time; short enough that it was up when you needed it, but not too much so that it was trivial.
More clarity on the white orb thing to transition levels and the boundary of the level would have been nice. Something like a little arrow that floats around your spaceship and points towards the end. It seemed that the second exit spawned where you killed the last enemy which is good, but you might miss it if you killed that enemy off screen. For the border, maybe you could have like an asteroid belt of asteroids very close together.
I was a little confused about the wording when you went through the white portal. It said travel through it to kill the corrupted planets. I thought it meant you were going to have to find another white orb and travel through to kill the planets (like you touch the white orb and it kills everything on screen). It took me a bit to figure out it meant "travel through the portal to go to a location where you can kill the corrupted planets". Honestly, this is such a minor thing and I'm probably the only one who felt this way.
You should probably put the game controls on the game page somewhere.