The piano tune was very pretty. It almost sounded nostalgic. I think it could have been built upon or made longer. Some of the sounds sounded discordant in my ears making me cringe a bit. That works in some songs, but this song is cheerful and upbeat, and it just doesn't fit for me.
If I were to do this, I would extend the piano loop to 16 beats instead of 8 beats. I really liked how the piano sounded at the end. I think THAT tune could have been extended too and linked back into the main tune.
Anyways, good work! I enjoyed listening to it. It made me feel happy and struck an emotional chord in me. Rating: 2 hamburgers and a large fry (with free water). 2+1+.5=3.5 units.