The gun has become WIN!
Ironically enough, starting from where you are now, a bit more exaggeration would rock. I hope I'm not contradicting myself now, I hope you get what I mean. As it is now, it's a great base for an exaggerated yet more believable motion with the gun.
But aw well, it's wonderful as it is. I totally love this shit mang. At such a small size you've come up with greatness! And I agree about the shadow, gife the animation life when you can <3