Definetly a cool concept! In a way it's almost a small "metroidbrania" where your knowledge is what allows you to move further and further each loop. I did however encounter a bug, it seems to have to do with reading a note a little before the countdown ends. This results in the reset sound playing but the reset not happening (since time is frozen while reading notes) When you stop reading the note time advances as normal, but when it reaches zero it keeps you in the current area. This can lead to a small softlock where half of the screen becomes black since the trapdoors shut again with you on the other side but the reset button worked great and I assume letting the timer run out would also have fixed the issue.
Other than that I also really dig the player character's design! Nice work and keep it up.