This is phenomenal!
Still... With the light coming from that angle, you are missing some important shadows on the sand. They would be very pronounced in this particular lighting, and would be angled directly towards the viewer.
I think even adding something subtle (in terms of a shadow) would make this picture 100 times more realistic. It's very good though. I love the rainbow in the center of the creature's sky. I can't figure out why something so big would be following an insignificant little human though!