I find it difficult to critique lighting if the photographer does not say what he intends. Did you want the shadows to be lighter? Use a reflector on the left side to bounce the light so it fills in the shadows. Some people may see a blown highlight on the upper right, but I think it is an interesting area of contrast.
Composition and focus are two easy criticisms to make, though. I don't think it is an interesting image in terms of composition because there is no context -- I'd prefer to see the surrounding environment instead of a close-up of a typewriter floating in the darkness.