Tons of fun! I'm not experienced with bullet hell (though MGGJ games are getting me there slowly), but I found the challenge level just about right on this one.
The artwork is excellent, I especially like the stage backgrounds. The music all works well too. Storywise, the first part seemed a little disconnected from the next two parts. Otherwise, it worked well.
The controls were interesting. I've seen complaints that they were too twitchy... I found them JUST about right. They could probably be toned down just a tad. The flight mechanic was neat... I found it a little hard to use though, and only really found it useful on a few boss phases. Most of my time was spent on the ground. I could probably get used to the flight controls if I needed to use them more.
One other stray observation, the first few times power-ups flew at me I ran like heck thinking they were bullets! I got used to that though.
I did two playthroughs (couldn't stop at the bad end!!) I managed to improve to Good Ending 3, score 51/100. I'll give it another shot once I've finished the other MGGJ games!
Great work!