Using sword slash as the bounce and as a fall velocity reset is really clever. It forces player to make the choice of taking the risky way of slashing in time vs "I'll just speed my way through and suffer after".
Art style is simple and cute, really dig the calming cave music you've used.
Gameplay wise, I personally feel it'll be much more intuitive if you could only die from falling on top of a block.
Great job! Thanks for making this!