That's a pretty neat CSS feature, Den! I've added that to the stylesheet, hopefully that makes it a bit easier to read. And thanks for the tips Lavos, those are certainly some concepts I'd be interested in going into detail with.
I've also updated the tutorial to include a section on Hit Points, both for the enemy and for the kid. That'll probably be the last of the additions for a bit, I need to get to work on setting up for the marathon!