I stumbled across some of this guy's videos on YouTube today - he is an absolute legend! Born in Hong Kong to Chinese and Japanese parents, Video Game Pianist moved to California when he was three years old and began taking interest in the piano at the age of 4 when, after hearing his sister play, he began imitating songs. His parents noticed his potential and enrolled him in piano lessons.
He then combined his two great passions, music and video games, repetitively listening to the Mario themes so that he could play them himself.
In this particular video he goes through a medley of pretty much all the Mario themes, and although it is 10 minutes long, make sure you listen to it from 9:15 onwards - possible the fastest bit of piano playing ever!