The trailer is HTML5, but the game is iOS. Websockets is used when you get to the "invite a friend" part.

We made this while our app was in the review process. I'm running Node.js on a separate EC2 Small server, so hopefully it'll handle a high load.

It works best in Safari 5... for some reason, Chrome is a little choppy, even with fewer trees. If it's choppy for you, try making your browser window smaller.