I agree with Tess to push the exaggeration of the guy more. Perhaps you could have both arms quite straight pressing on the tub in an attempt to get him out of the water or even having one leg half out of the water (covering up his dedicates witha few well placed bubbles of course)
NoWayMe made a good point of making the shark bigger than the man, but it would be nice to see that he is still fitting in the tub properly. It could be interesting to add his tail behind the man kinda like a backrest so that he has nowhere to escape to. The gesture of the piece seems to form an almost C shape and I think it would be more exciting to push the size and curvature of the upper part of the C (with the shark being the upper and the guy been the lower)
Depending on the lighting you could even add a cast shadow of the shark onto the wall to push the presence of it a bit more and/or you could even expand the area of the tub where the shark is sitting with maybe the tub beginning to crack and water seeping out.
I would move the boat or do something more interesting with it as it is a little distracting. Maybe it could be in the shark's mouth or in a puddle on the floor which would flesh out the empty space in that area. It would also help to show how the water has been displaced in the bath (a shark would probably take up a decent amount of the space :P)
I have never seen a bath directly on the floor. It would also create a nicer silhouette!
