It's a fun viewpoint, isn't it :)
It makes me realise that this painting is definitely one that is best viewed up on the wall. I guess when it is hung slightly above us it just helps to exagerate the unsual perspective and makes you feel that you are looking up at him as he looks down at the worm. Play with this image below and you will see what I mean. Look at it straight on to the screen and then lower yourself ever so slightly (or raise the screen if you have a laptop) as if you are looking at the painting on the wall.