Nemo,
I'm actually not impressed by his performance - probably because my son has been doing the same thing for years and I regard it almost as a bad habit. I refer to it as "mood music" when he does that and usually tell him to stop since it is undisciplined... it amounts to just dinking around on the keyboard. If it's not written down, and can't be written down, and therefore cannot be repeated, what's the point? I don't know if it's even improving his technique since it's just a lot of doing what comes easily to him.
I think if you listened to this young man play a dozen "songs," you'd quickly see that they all sound the same. He probably can't read music and therefore can't compose. It's tuneless and unstructured, just droning on and on.
But the judges obviously feel differently. Maybe they're singers or producers, not musicians (my son would take issue with what I just said, insisting that singers ARE musicians) and they don't know that what they're seeing is relatively easy.
| 
