The shoulders look fine, imo. Some problems lie with the proportions though; his torso is way too short, and I think his legs are either too short, or not bulky enough (possibly both, but its hard to make sure what the issue exactly is without first changing the torso).
There should also be a split at the crotch, other wise strange things will happen when you or anybody else starts animating it.
Keep it up with the cell shaded renders ^^