This is super nice! I love the juiciness of the gameplay and the really smart mechanics. Very well made! I can tell that a lot of care went into making this.
Personally, I would have appreciated if the difficulty was a bit lighter. I'm not a big player of platform games, so I understand I'm maybe not the target audience. The game feels like it's tweaked for someone with a bit more... skill :P For me, an "easy" mode with some checkpoints would have been welcome.
I don't know if this is helpful, but here's a screen capture of me playing for a bit. I thought it might be useful (or funny) for you to see which parts I struggled with. ;)
Oh, and I love being able to choose a palette at the main menu. Brings me back to playing gameboy games on a gameboy color.