His torso looks unnaturally bent out of shape near the center. The lines wouldn't really go off to the side like that because they are simply lines in his torso, they would curve with his torso, at least, thats what I think. His Drill is incredibly under detailed and looks really out of place compared to the rest of it. Also, what are you trying to accomplish with the arms? They look like your trying to make arm-arms, but they also look like your trying to do flippers at the same time. You're not really hitting the in between. Since this is Pokemon, and generally cartoon y, I think you can get away with just having the flippers flat and flabby while acting as arms would when they are in motion. There is some inconsistencies in the thickness of your lines. In the darker areas of gets thicker for no reason while in the other areas its really thin. I highly suggest not outlining the dirt to make it look as flat as possible next to the sand whale and make him pop out more. Use thicker outlines on the whale because I really do think it would look better with a thicker black outline then it would look with a solid black outline that does not use a lot of AA.
Good job nonetheless.