Using Chrome 11.0.696.50 beta here. It took a while to setup in that I got a partial skybox and a few jellyfish popping up and then a few more and then a few more after that. I thought the camera or scene was changing because it was so jarring. Once setup though, it works pretty well.

I get 8-9fps with the default settings. Reducing the count of Jellyfish to 5 gave me closer to 20fps. Reducing it to 1 and turning off Skybox and Particles gave me about 40fps, but didn't look nearly as cool.

Very nice demo.