I think the main issues are the light and crop. That said, I'll tackle the crop first.
I might suggest have the tip of the arrow in the shot and cropping more for it to have the feel of a panorama. You can crop some of the bottom of the image with out loosing the feel of the pose.
As for the light. Not knowing how you had this lit it is difficult to say. So I'll just say what I would have done.
Using a diffuser of some sort, in front of a single light source placed to the right and slightly below the elbow, I would have angled it so that it did not fall directly on the elbow but just below. This would help give more definition to his entire body and not have the bright area on the tip of the elbow.
A reflector of some sort placed low to reflect the light up on the front towards the hand holding the bow would help define that area and even out the rest of the light, while still keeping the intriguing shadows.
Really, this shot is very well done already and just a little tweaking would make it perfect.
Too bad you had to crop the arrow point. Very nice idea. Lighting is good but I find too dark in the left lower corner. The overall image could have been lightened just a tad, even considering your title.
Good composition. I had noticed that many people has tryed to shoot dark scenes like yours. But they has a lot of issues about focus. May be you had tryed to do it with the AF. The AF don´t works well with low light situation. If you don´t has MF capabilities, try to show normal light conditions then do a brightness adjust in PS.
Great idea here... the brightness on his back elbow is slightly bothersome, and I wish I could see the whole bow and well as the arrow. I like the anonymity here though, nicely done. Interesting lighting. Good luck.