I believe the relevant lines are

    @-webkit-keyframes ball { 0%, 100% { left:30px; top:107px } 30%
    ...

and

    -webkit-animation: player2 4s linear 0 infinite normal;

which define the animation keyframes and parameters.

See the webkit blog for information on how it works:

http://www.webkit.org/blog/324/css-animation-2/

Interesting. Thanks. :)