Bear in mind that the whole point of this exercise was to produce a game without using any JavaScript whatsoever. It was intended to be more of a technology demonstration than a playable game. As the article pointed out, you can find a much more accurate and playable implementation of the game on the Pica Pic website. http://pica-pic.com/

Love it! But yes, needs keyboard support.

I was just reminded these ever existed 9 hours ago by Crash Course Games: https://youtu.be/ZEwbHWspFWY?t=2m35s

Yeah, the flash version they link too has keyboard support and is much more playable for it!