Most of these things (if not all) can be done in Firefox. I'd assume the point of this is to show off the cool things you can do with "HTML5"-- and making it work in just one browser seems to go against the goal.
It's not about making it only work in one browser — it's that currently these effects collectively (as Arnorhs points out, this isn't just box-shadow) are only rendered properly by that one browser (actually it's the rendering engine which is most important here — WebKit — which means I can view them fine in Safari 5.1).