The water and the light from above is rendered nicely, and the figure looks good. The idea is fascinating and an apt metaphor for crushing debt. The composition is well constructed, as he and his burden are the focus of the painting.
That being said, I am confused by lighting of the subject. With the bright sun coming down from above the water, he appears to be too well lit from below. What is down there from which that light comes? Sand is reflective but unless one is very close to the sea floor (much closer than the man is) there would not be enough of a light source to cast the highlights on his skin. It takes me out of the setting and onto a movie set, where such lighting is used to make sure the actor's face is visible. In doing so, his struggle seems a bit artificial.
Also, heavy chains such as those holding him to his weight would not break gravity's grip on them, even under water. They appear to be floating as if made of a much lighter material. It gives one the appearance of a prop and not a genuine hazard.
You could chalk it up to artistic license, but I'm unable to feel his panic. This is a great idea and your technique is wonderful, but it doesn't drive home the struggle.
Thanks Smiley I appreciate the criticism however this is a magazine illustration created for dramatic visual effect not realism. You're exactly right, just like a movie the lighting was rendered that way intentionally so you could see the expression on his face and clearly understand what was going on in the scene. The chains floating (and his whole body in fact) was created to make for a pleasing visual composition as well drama.