Love the art style - the choice of colours, and the way they change as you progress, and the cutle little bouncy animations all the different elements have. The music loop is enjoyable for the entire duration of the game, and I like the quirky dialogue.
The game could do with a bit more feedback when things die - when you jump on enemies, they just disappear, and when you fall on mushrooms, the level just restarts. A few sound effects, and a maybe some particles would really polish this up.