Hands off I'm really keen on the unique vibe you went with. It truly gives off a mario kartsy / whimsical vibe and I like it. While I think that while overall the melody is cool and charming, I also see how there could be some things that could be fixed. One of my biggest issues with this piece is the mixing. I'd say the guitar that's playing the chords has some weird frequencies that should be worked out in the mixing that clash with the melody and other background instruments. I also believe that the backing instrument that develops further the melody near 2:10 has to big of a reverb that should be lowered. Also the main instrument at around 1:30 that sounds to me like a modulated saw could be lowered in volume. I overall really like the structure of this piece and don't have a big issue with the composition as like I said it's fun.