This is an astonishing demo -- and I very nearly missed it, because I thought the scrolly graphic at the top was just a fancy animated header, followed by a bunch of text that seemed to be refering to something else. I only discovered the full demo when I accidentally scrolled up, and found it lurking there well above the start-point for the page. I can't help but think that a lot of other viewers must be missing it entirely.
So a note to web-masters: please put any content you want your users to see below the top of the page, not above it.