Decent point on not knowing how big your window size is - think I'll update to include a width counter on the start screen.
Reason for the resizing down at the start is simply so only certain parts of the animation show at different times. It means I can control what width the animation is being viewed at, as otherwise I'd have to animate everything across a very large width potentially, which would be pretty time consuming, as this could be huge. Think with the feedback I've had, will release as a non media query animation as well when I get chance.
It took me a while to realize that the resizing was the whole point -- the scene animates as it gets wider.
There's nothing ground-breaking here, but neither is there in many of the XKCD stunts that we fawn over here. I think if you just describe it that way we'd all know what's going on.
I explored a few options - the reason I decided to make it controlled by the user was so it didn't have to open in a new window (as you can only control the width of the window with JS in a separate window).
Thanks for the feedback though - might create a separate self-running version at some point.
This only works when resizing the window? Would an ever-increasing div work? If you floated it right the size would always increase on the left, mimicking the drag and resize action that the user is doing.
That said, I get that you're pushing the limits as it is here and you've likely already considered this as an option.
I'm using a tiling-WM and the resizing window thing was a bit annoying to me, and was somewhat distracting from the demo. But other than that, I'm impressed and I had lots of fun playing with the css to see how it was built!
Perhaps I'm missing the point, but it would have been better in my opinion if you'd found another way to make it auto play in whatever window size.