I love the concept, the style everything but the boss fight at the end has a couple of issues.
To start with the hit detection is a little off as I got hit a few times when he wasn't touching me, and now thats not just me making excuses for how he killed me a few times, there was quite actually clear space between us and a few times where I cleared his attacks yet still took damage
also during the sequences where the platform ends and the orb to switch the world shows up, it was late a few times to where I didn't have enough time to hit it then land and dodge the bosses attack and even when I dodge the initial attack I'd still get hit when the boss reset to the right side of the screen and I didn't have enough time to dodge after landing.
Speaking of that orb switch, I found a couple of times when it would show up the boss would pull that downward slap attack after hovering right on top of the orb making it harder to hit
My last gripe might be more of a personal preference but I wish that boss had a health bar as I hate it when bosses don't have them and you just have to keep attacking not knowing when their going to die.
but other then those issues, I liked it, it was a cute platformer.