Hey, this is a really fun game
Your sprite work has a lot of personality, especialy considering the limitations. The controls are nice and responsive too. I don't think the inclusion of the sword is really that important, since most of the time you are mainly jumping, but that's a small nitpick.
I really like how you implemented the theme in this game. Platforms switching on and off to the rhytm of the music, as it gets faster and faster is a really cool idea.
However, I think that there is a problem with sound design. You see, I think that the music should have been the only thing that's playing. Not only do the sound effects make it harder to follow the rhytm, but it's also just against the rules of the jam. It is written: "one audio channel and one sound played at a time. " Your game however, has many sounds playing at the same time.