I really like that you're going for a more extreme perspective than you usually do, great job
I do think it would be nice with some space between the gun's nozzle and the border of the painting, to me it feels a bit 'cramped' right now.
I'm a bit unsure where you want the focal point to be, the gun or his face? You have a nice little lightsource that draws my eye, but it competes with the gun for my attention.
I was also thinking that maybe seeing a bit of his ( very foreshortened ) arm would add a greater sense of depth to your painting and also help his gaze travel along his arm, so to speak.
Keep 'em coming!