It is an interesting idea, and a nice symmetrical composition, but it's really more of a silhouette than a shadow.

It may be a problem of monitor settings, but on my (calibrated) monitor the shadow is barely distinguished from the very dark wall.

This shot is so freaky, .. I swear the shadow grows while I'm looking at it ... very cool shot.

Such a brilliant idea - but on my monitor it doesn't really work without alot of squinting!

Ummm... someone's monitor needs to be calibrated right away, either mine or yours...

Have a look at the histogram of this shot and I think you'll see why. Much too dark.