this can be greatly improved (losslessly) using http://punypng.com / http://www.smushit.com/ysmush.it/ / downloadable PNG recompressing software. I tried it on several files on this site and some decreased in size by more than half.
I wouldn't say it's crazy big. Bigger than 99% of one page sites? Sure. I've got a 50mbps connection and even with a far slower one, this would only take a few seconds to load.
It took me a couple of minutes on a 3G cellular connection.
It was worth the wait, for sure, but due to the way it rendered, I felt like I had to watch the whole thing because I didn't want to miss something neat.
It could (and should) definitely be optimized a lot, but as a proof of concept, I'm not going to quibble over file size, even if I'm negatively impacted.