Nice game! The platforming was quite fun and the sound effects were good. I think the combat could be improved (and did that boss go down in like 4 hits?) but as a platformer, it was really good.
Maybe this was just me but I got a little thrown off by the parallax in the background, meaning if there was no foreground objects on the screen, I couldn't really get a sense for where I was going. Potentially a few more objects could fix this and also flesh out the level so that the platforms don't look like they are just floating in empty space.
Overall, really good game, graphics were super clean too. Great job :D