The speed in which it was meant to be played, without a single error.

God, I fucking love it.

It's incredibly difficult to play.

I dunno man... it's technical... but it's like watching Yngwie Malmsteen masturbate over the fretboard, or Mike Portnoy wanking all over his drum set. I can't feel a soul, man.

Well, to be fair I've seen quite a few people play it slower as to have more "soul", but the song is meant to be played at this speed. I think she incorporated as much "soul" she could into the performance, with the crescendos and such in places that weren't there in the original.

And I'm unfamiliar with Beethoven (I like Baroque more than Romantic, sue me), is her meter supposed to jump around at a few select places?

Potentially. IIRC it's not uncommon but I don't read sheet music, so I wouldn't know if the song is meant to do that.