Whatever interesting CSS features this game contains could be applied to more practical use via a different sort of implementation -- in this case the reason is solely to get away with not having to write a line of JavaScript when clearly JS is a better way to write something like this.

It's one thing to write something that uses 30 lines of JS code only, than to create this and say "Look Ma, no JS!!"

You're still missing the point. It's a cool demo.

We're hackers. We're supposed to like things such as obfuscated c competitions and 5k demos!

I hate using javascript where CSS would suffice. It is more "natural" and efficient. The resource consumption is less intensive.

I'm still slightly uncomfortable with css being able to do anything more than positioning, coloring and fonts... and maybe hover selectors though I did abuse those severely when I found out about them.

Nevertheless, demos like this are pretty cool.

That is because the animation capabilities of CSS are still meant to be used for presentation purposes (like a cute response to mouse movement or a head bobbing around), rather than an all out game engine. The idea is still cute, but I freak that people will think this is the new way to design online games.