Now what happened was super cool, I was not managing to get the good ending (a 51 second last level), then I switched to another browser and I got the bad ending (a 33 one) here, then I got back and got the 51 second good ending on my very first next try.
The game is excellent. The controls are perfect and the visuals as clear as you can get. The levels are different and the difficulty of the last level depending on the time spent so that it's harder when you're targetting a higher score is a super cool idea. I love the music you used and the numbers hiding your character in the last level is hilarious, was it intentional or not. The difficulty was exactly how I wanted it to be at the moment. Also game is pure bullet hell with some cool patterns to deal with by the way.
The game is very polished and I had ton of fun playing it, congratulations.
All the levels are super great, it's impressive that you managed to have them beatable by always rushing forward (or at very least very close, there are a few parts I did not manage to do this way I think so I can't be 100% sure but they did seem like it) in such a short dev time, you deal with it fast as a player but that's quite some content you put there, is this the first precision plateformer you've worked on?