When I played this on the piano, my mom said "you know, usually songs do more than just repeat..."
Sorry Mom. Anyway, the version in-game sounds very different. Don't be surprised.
I've been trying to study how 8bit sprites were made and it is facinating. The limitation of the hardware made people be creative when it comes to making games for the era.
I also been using a shader to see how the characters look and how the shapes change with that visual.