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.