Cool concept and loving the use of the theme! Im sure puzzle game levels are hard to come up with and with such a short amount of time you came up with 5 on top of implementation, nice job! Would love to see this further expanded upon with more complex levels and maybe even more mechanics thrown in.
Id probably only complain about the music repeating when changing scenes but others have already commented about that, though I would also maybe say pick a longer track. And maybe some more things thrown in the background to stir up some more atmosphere.
Cheers!