The design and illustrations are amazing. Unfortunately this kind of effect gives me immediate and lasting vertigo (lasts a couple of minutes past viewing the site) when used to this degree. I'm not sure if I have an extra sensitivity to the effect.
Interestingly, it's the same vertigo I receive when someone rotates an arm-mounted screen while I'm playing an FPS game on it.
I had no idea it was possible to reproduce that with simple 2D effects. Science for the win, though my stomach does not thank me.
This artistic style of depth, or what little I could discern before I had to close the page at least, reminds me very strongly of the iOS game 'Ramp Champ'.