The example does nothing for me. Just a white page and errors in the browser console. That's not very compelling.
When I started (firefox) it was just a grey page with a frame rate graph in the top left. Turns out it started zoomed in way to far. Really cranking back on the scroll wheel revealed the map.
Except it's zoomed in so far you can't see anything unless you zoom out, and then zooming out too far breaks it (chrome 66). That's why screenshots and explanatory text are good to have. I like it, it just feels not-quite-finished.