how was playdulla.com made?

I know its html5 and css. I can do the layered background thing I just haven't figured out how they get it to move when the mouse moves. I looked modernizer.J's and parallax.J's and I don't believe they do it. I'm not a javascript guy though.

Any ideas on how they accomplish it?

http://www.jquery4u.com/animation/jquery-parallax-tutorial/
jQuery Parallax

I looked into Parallax before I posted and the more I toyed around with it the more I thought it was just a background image rotator. I went to the parallax site though, your jquery4u site made all the difference.
thanks kralcx