There's a link to the download page for the engine just underneath the game. The rest is just some images, a few JS files and one CSS file:
http://audenneedham.com/game/index.html
http://audenneedham.com/game/ENGINE/game-min.js
http://audenneedham.com/game/ENGINE/controls-min.js
http://audenneedham.com/game/ENGINE/engine-min.css
A friend recommended trying gameQuery out next time - looks a little tidier - the one I used was all compressed JS and kind of ugly to work in: http://gamequery.onaluf.org/