I noticed that too about the drums, also there is some keyboard work that you can't see. I'm thinking that either he played over the original midi or they were dubbed in later.

Seriously though, I can't understand why you wouldn't think this is real. Just watch some of this other vids. Or Watch his  fingers as he bends the notes. That sort of thing would be hard to fake. Also, why would he go to the trouble of learning all those fake notes and getting the timing down.

He wouldn't. He's just that good. And FFVII is just that popular even 10+ years after its release.