Actually the first vid in the OP is an epic fail.
I stopped the first vid when I saw this.
http://img852.imageshack.us/img852/1677/pianon.jpg
The highlighted frets are the ones played at the same time.
This shows a position that human articulation can achieve in no way.
No way you can open your hand to catch 3 D.
I (but everyone with minimum music knowledge) can write something even harder to be played by a piano roll or a midi.
Hardest thing should be something playable in reality by one highly skilled human.
If you put 2 people to play that stuff, it becomes totally ordinary.