Amazing game and solid execution! Really loved how you could come up with so many different puzzles using the same basic principle. The dual purpose design was nice too. Not only do your bullets damage yourself, but they can also be used to gain additional knock-back and speed which was especially useful in the time trial stages. My only feedback would be to add a button to restart the stage and to look into the time slow ability since the time trial stages felt much easier using it despite struggling so much beforehand. It was so satisfying to finish every stage and even more so the game. I think you have the potential to take this even further because it looks like you can easily add complementary puzzle elements to the main mechanic.
P.S. It would be great if you could play my game :)