Wow. Lots of fun. I spent a lot more time playing this than I thought.
I think everything was done well, the sound, the graphics, pixel snapping, physics feels nice....
I think my biggest frustration was that my aim was reset each time, and there was no indication of how much power I did last time.
Yeah, I think that makes the game harder, but I just kept counting the number of times I hit up, and the number of power ticks that passed. I would have been a lot less frustrating not having to count 14 ups while fine tuning between 5 and 8 power ticks.
Other than that, it was great, and I didn't want to stop!