Very fun to play. I agree with Isaac that you utilized the dash well. It felt nice to move around using only the mouse so I could focus on enemies and avoiding projectiles without having to press too many buttons. The music really adds to the experience, and when it changes during the boss fight I was like WOAH. Nice transition there.
Sadly, I couldn't defeat the boss. It's a good fight though, and I agree that the dash needs a bit of a buff to make it feel more balanced. It was cool to see some new types of threats as you progress. Really solid game you made, impressive that you managed to develop so many features in so little time. Awesome work!