The bow is actually rather accurate. I shoot compound archery, which is different than traditional longbow, but the concept is the same. I could take some pictures for reference if you like. Only thing I would mention is that his left hand grip is a little strong. And you could make the arrow more prominent, I have some pics again if you like.
I would write a critique, but I can't oh well This is genuinely fantastic, I like your twist on the doctors mask. the overall... mystery, darkness, and foreboding of the piece bring it all together fantastically. the only thing that caught my attention in a negative way is that it would be stupendously difficult to fire a bow like that, I mean with the drawing hand facing downwards and two fingers on the string generally a bow is fired with the palm facing towards the archer with two fingers below the arrow and the pointer finger above... only thing I found, and it's not even noteworthy. Amazing work of art, fav'd.