He has a very truncated chin. Or is it just his beard that makes it look like that...? Not that it looks unrealistic, mind you - he's just not very handsome. Which was probably your intention, so good work.
How many division levels is that? The beard is amazing. Done in zbrush as well I'm assuming? Do you have a link to a render in just a Matcap; I love to get a good look at the sculpt. Thanks!