Note: though I've upped this, I recommend actually just going to the source link to mess around as 1) lots bigger and 2) he updates it with fun new stuff occasionally.
Works fine for me. Perhaps you missed that you need to click on the gap at the bottom-right to play the animations?
Okay damn, dude you are completely correct. I downloaded all sorts of alternate Flash Players down into my PC last night just to run the Flash and I was so frustrated when they didn't, stayed up until midnight just to try and get it work. Turns out all I had to do was to click on the gap lmao.