Why do you find it amazing? I saw this first probably 10 years ago with java applets. Is it more amazing because applets are unfashionable?
The interesting part here is that it is showing that browsers and JavaScript, with a very different approach than Flash or Java, can now handle this sort of computationally intensive, graphics intensive application without any OS-specific plugins.
Wake me up when that means something from only 5 years ago and not 20.
thats a plain miracle.