This is slow as hell. I do not understand why people think HTML5 can replace Flash. Flash is big and bloated but still perform better than HTML5 in all the so called demos i have seen.
What browser are you using? I've tested it on Safari/OSX and Chrome/Windows, and it was perfectly fast and responsive, even on a three-year-old budget laptop.
I was using Chrome and found it surprisingly speedy. At the end, I was able to whisk from slide to slide faster than I generally can do anything on my computer.
Wasn't that slow for me on my netbook, but doesn't have any scrollbars, which meant I couldn't see a large part of the bottom @1024x600.
Give it time. And it is not suppose to replace flash, just greatly reduce its scope.