The Physics of Super Mario Galaxy.

I’m loving this game (about half way through I reckon), but if I have a complaint, it is that the visual resolution of where you are in all the magnificent 3D-ness is a little underdetermined by the graphics you see. Hence the shadow under your feet “as if light in Mario’s universe always falls directly toward the nearest source of gravity” is not only essential, but I find i spend more time fixing on the shadow than on Mario!

To be fair, the game designer recognises this as mentioned in this Gamasutra interview.