The most impressive part of this demo is the details. The colours, the fluidity of the tadpoles’ movement and the music make you feel like you’re watching movie titles. You can almost see where the opening credits would come in!
It uses derivatives in the shader, which is an optional extension in the WebGL specifications, and as far is I can see, its only supported by Chrome at the moment. If you have the HTML5 audio API enabled, it reacts to the music (very basic, just some speed adjustments).
This demo only appears to work in chrome at the moment, and Kris has written up a post with some of the details behind the making of it.