Thanks! I never set out to make a rage game but I guess I couldn't help it 😆
Indeed, I was very unsure about the music transition. I thought some contrast was needed since the beginning is so calm but then it gets intense, but maybe not as sudden and intense as the music suggests. I was going to try to improve it (especially since the metal music part is very badly played), maybe building on the piano melody as you said, but then I had to fix bugs and ran out of time. A music/sound rating seems like a good idea to me 🙂