I may have unintentionally misled you a bit in my previous feedback. Shadows and light sources are definitely okay on diffuse painted models, but I personally would avoid having completely black (and white for that matter) areas. It looks like you removed most of your shadows after my post. I think it's perfectly okay to…
Sorry for the confusion. I meant the cast shadows, mostly on the lower areas of his body. Comparing to Shotgun's image, your clothing areas get really dark. The cast shadows on the skin area are also a bit dark. It's good to paint lighting in like this for diffuse only models, but be careful with going too far overboard…