Hahaha, I love this, it's so cute and charming! I really enjoy the overall balance between the instruments, the different textures you introduce throughout the music, and those little chromatic movements that keep the listener on their toes.
Since this music has such a 'Nintendo-y' vibe, I think this video might help you come up with even more ways on how to make your piece more interesting: https://www.youtube.com/watch?v=-x1kn0-HIO8
The concepts introduced in this video really helped me out when I was composing Nintendo-style music, I hope it's helpful for you too!