Your Jim is awesome and yes, you've really improved your skills. But there is still missing something... his sight. It became not as straight and deep as he had in his movie appearence. This rebellious eyes - that what is missed.
I think more round eyes would be more beautiful on him because he is with my age,that means a teenager between 18-20 my opinion is this , if you want you listen if you want not .By the way... Great draw ^_^