Mhhh though one.
This is an OC, and OC's are know for their simplicity (well not always lol), Crombie's critics were kind of true, but that's not a valid point, because we don't know for sure what were you aiming at.
I'm going to assume that you were aiming for a realistic style, if that's the case, the only little thing might be the "light management", other than that, it's pretty much perfect. really.
Remember that no one can see the drawing like yu do until you become a master of it, sadly people often see errors or stuff like that when we actually wanted for our drawing to "look like that". XD