Very nice! The texturing and lighting are what really makes this demo. Unfortunately, it only displays correctly for me in Firefox Developer Edition, not FF 33.0, in which the picture is skewed: http://i.imgur.com/7i74m36.jpg.
If you're into tiny cube-based 3D engines also have a look at this demo for the Lobster programming language (http://strlen.com/lobster): http://i.imgur.com/ZZWFkXn.jpg. Its entire source code fits in the screenshot.