Man really good work, especially like the third guy with the missing patch of hair.
If it's going to be used in a game or something, I feel like the first two might be too similar to be easily distinguished - considering the difference in the jawline, maybe if their hairlines followed, so the second with the narrow jaw had the wide hair and the first with the wide jaw had straight hair, their lines would be a little more distinct. Of course, that first guy does have that whole burly soldier look, which it could totally ruin! Just my 2c, and like I said the shading and general lines are v. nice.
Thanks 7heSama