Here's an excessively rough edit:
Right now I'm not sure which bits of the snake are meant to be out forward, but in the original it looks like it's swerving left and right but mostly outward until it curves back into the wall at the top?
The light seems to be coming from the very bottom, stretching up the wall. If this is the case, I'd expect to see much more of a cast shadow stretching up the wall, too. The "segments" of the belly in the original are very straight, giving no sense of the cylinderness. Some of the lighting on these segments also seems to emboss the segment. How pronounced are the segments supposed to be? If very, then perhaps it is worth considering the form of each separately, otherwise the segments could simply be hinted at with smaller details.
