I liked it. It's a very polished platformer, and the level design is excellent. The music is catchy, and the visuals are bright, vibrant, and overall very aesthetically pleasing.
However, I wanted to pause the game near the end of a level to check a message. When I hit escape, it sent me straight to the menu, no questions asked, losing all my progress in the level. I think your game would benefit from having some kind of pause menu, or at least a confirmation before exiting to the menu. I tried almost all the keys on my keyboard hoping to find some kind of pause or menu, to no avail. A "Restart from Checkpoint" or "Restart Level" would be great.
Overall, it's very promising. I'm excited to see where this game goes.