Funny, while listening to my laptop's fan going crazy I was thinking that any computer from 2000 would have enough power to render this if it was native :P

I can absolutely make a native version that's considerably less efficient than this one.

And yes, a more efficient browser version is possible (and possibly simpler). People like to fixate on platforms, but it's all about implementation.

Sure - also on your computer from 2000 the fans would be on all the time time, one fan would have a bad bearing, and the HD would literally be making a crunching sound, and you would constantly be cleaning gunk off the mouse ball.

Oh, what satisfaction there was in removing the gunk off the mouse's spinning rods!

Move to a trackball and you can still have that fun today!

It "performs well" in the sense that I as a human enjoy it smoothly, but it does make my modern laptop's fan spin up quite loudly; and I don't know (I could be wrong!) that it renders graphics that is effectively fundamentally more complex than the ones I enjoyed on Amiga 500 and x286?

This is not in any way to reduce its awesomeness; I just lost 15 minutes I don't have scrolling around and will return to it this weekend! But I wouldn't say it had great performance.

edit: Unless you meant "Stellar Performance" in the artistic sense, i.e. "The figure skater put up a great performance today", in which case wholeheartedly agree :-)