Its 2D tile graphics engine is powered by HTML5 Canvas, with browser-to-server communications handled by WebSockets. Sound effects, meanwhile, are powered by HTML5 audio APIs, and each player's progress is saved using localStorage. The game also supports lots of simultaneous players, thanks to a JavaScript-coded backend that runs on Node.js.
So you have seen all the cool stuff WebGL can do, how do you do it? Well, turns out it is not too hard with Three.js. This short presentation shows how to do cool things with WebGL.