Vader looks... so completely and utterly disinterested. He's practically just holding his lightsaber out there more like its an exercise in patience rather than a fight. Yes, I grasp this is probably what you were aiming for.
The über-huge Star Wars fan in me is weeping with excitement at how bad-ass this drawing is, especially since The Empire Strikes Back is my favorite of the original trilogy --- "I love comic books and I love anime. Its kind of like being in a crack house with no money.- Samuel L. Jackson