Well done with this game, it really shines. The pixel art is incredible, I love the retro color palette and the menu animations were great too. There was one thing I noticed which was the character sprite when jumping does not have a complete white outline around it like it normally does. It's missing a white line on top of its hat, which is nitpicky but maybe you missed it and I can help by saying this :]
Overall amazing game and I hope to see more levels. I didn't think they were too easy, but maybe they will eventually be the first few levels before they start to get more difficult.