It's broken on Chrome 19.0.1084.56 on OS X if you open it in a new tab in the background with middle click. Plain black page, arrow keys/space changes the number indicator in the URL, but shows no content.
Edit: and on a related note, personally I really dislike the trend of posting slides for review outside of the context of a presentation. As something to click on from the front page here, or to bookmark/print for future reference, a plain page with a list that you'd just scroll up/down normally instead of separate slides would be much handier.
It would be nice if it didn't hijack my attempts to zoom in and read on my phone. And some indication that swiping changes slides depending which way you swipe.
I got the title slide and was stuck. Took me a while to find out that the space bar skips to the next page. Then I found the invisible 100px wide buttons left and right of the slide area.
Very annoying but I guess it looks better as a presentation. At least the mouse wheel should work, that was my instinctive reaction to skip forward and you could add that without affecting the visuals.
I viewed it in Chrome on Linux and it took me quite a while to figure out that you advance by clicking the solid black bars on the side of the slides (which don't even show if your browser window is too narrow). More of a UX issue than a technical one, I guess.
The problem in Opera is your feature test in slide-deck.js line 762. At the time this part of the code executes, the DOM is not ready yet, so document.body is just null and the whole thing fails.
It does however work perfectly after executing window.slidedeck = new SlideDeck(); manually.
FAIL - apparently the presentation does not work properly for half the commentators here. The world is clearly not ready for HTML5 (not everyone uses chrome's flavor of it either) yet so make it work with other browsers as well.
Well, a big problem is that you're got a pretty huge sampling bias there. The people that it works for aren't going to comment to say "it works!" because that's the state that they expect it to be in.
It works fine for me -- Firefox 13.0.1, so it's not just Chrome-flavoured html5.
As well as the sampling bias pointed out by jdpage, the breakage is also the fault of this particular HTML5 presentation framework – it is not necessarily the fault of HTML5 as a whole. The page’s user interface could make it clearer that there are more slides and show you how to go to them – for instance, by showing the invisible buttons along the side on page load. And it’s possible that the JavaScript could be written more compatibly, and have better fallbacks for when the browser doesn’t support certain things.