This guy is a joke, and so is the video.
First of, the introduction ("This is the one of the hardest piece ever, now it's twice as hard!!!) is just laughable. He is obviously very full of himself.
Secondly he only plays the easy parts, where one can 'easily' just use muscle memory for both the bass and treble. When that isn't possible, he just uses one piano!
Thirdly, that look at 00:56... Very funny.