I like the overall design, and the video is damn inspirational. Very fond of how they made little cardboard widgets and put the HTML on the back, cute :-) However I didn't even know there was anything below the fold, until I read this comment thread, looked like a video page, is all. And as I scrolled, the page lagged like a wild goose. Designers might not have the chops needed to analyze the JS onScroll render/paint cycle times. Scroll performance is so essential on a parallax scrolling effect - and there are so many hacks to get it done performant. Doesn't look like this makes the cut.
What hardware are you on, what browser are you using? Because I have a retina pro and loads of websites scroll much worse than this (f.e. http://foundation.zurb.com/learn/features.html). It also worked fairly well on my WP8. I'd say this is just a tradeoff between graphics and performance.
