Perfect use of the theme, funny voice acting and dialogue (that might get annoying in a longer game, but it's perfect for a short game like this), smooth and simple platforming, great visuals, and even an unexpected vehicle section. This game has it all! All wrapped up in a perfectly paced, short package.
The only thing I might suggest changing is simply adding some sort of particles to indicate the sun is your source of power, for those that don't get the solar panel hat.