Why would someone, capable of this seemingly superhuman ability to improvise on "Mary had a little lamb" even post a Chopin-Godowsky midi in the first place? I would think someone of this caliber would have a busy concert schedule, an agent, and a website. Can you provide this? I've listened to way too many recordings to be able to tell the difference. As for your chopin etude - I haven't heard it. However, a single chopin etude would be much easier to play perfectly than a sick improv like this. He most likely ripped it from a cd or something.