Very nice retro aesthetic. Also the music is great, and fits the game very nicely. The controls need a little bit of improvement (but this is usually the hardest part to achieve on a plattformer). My suggestions are: Try adding some "coyote time" and some jump cache, and making the player's and enemy's bounding box a little bit smaller. This will make the game easier, but you can try adding difficulty in other ways (more enemies and traps that require precise controls).
The game is beautiful overall and I enjoyed it. But if you add this improvements you could easily expand it and make a large game that many (including me) would certainly enjoy.
Nice work!