Hi Ferg, that's a cracker! Love the understory there... is he off to kill someone else? Or just himself? If the latter, I think the gun placement works well - it probably should be pointing towards him!
Re: lighting, I'm no expert but I'd mention the following as a bit of a guide:
1. hard shadows (with a fairly definite outline and very little "blending" from shadow to non-shadow - always made with a small light source, e.g. uncovered flash) in simple scenes can work well and can often become part of the composition. In more complex scenes, they have to be used carefully otherwise they can start to compete with the actual subject for attention.
2. hard shadows can be used to tell a useful story themselves: backlit scenes with hard shadows coming towards the camera give a sense of imposition, light source at the camera with hard shadows falling away into the background often say the opposite.
3. soft shadows, on the other hand, can be used simply to provide clues as to form and 3D nature of the scene: they're always from a large light source (e.g. big softbox or by bouncing a bare flash off a wall/ceiling - one of my favourite tricks) but are usually a lot smaller than hard shadows and their edges always blend away smoothly. For this reason they're usually not distracting at all and can be used on the most complex scenes without distraction
I find with lighting the trick is to position the light(s) so that you get the right areas lit but then also the right type, size and position of shadows. It's a balance between choosing where you want your highlights to be as well as where and how you want the shadows to fall. I think in your image, hard shadows could work well but I might be tempted to throw the shadow more towards the camera (and therefore gun) - so flash behind subject, either high or low - which would almost certainly require a little fill lighting from pretty much on axis (i.e. from the camera).
Great shot though and the lighting chat above is just because you asked!