Great playful mood in this image, I like it. Great pose, expression, composition, beautiful tonality ... I think the busy-ness of the background distracts, though. A wider aperture would have blurred that out a bit more, placing more emphasis on that handsome, happy young man.
Excellent light and definition. I love the transparence and the tone of the grey you optained. I find the persons in the backgroud make rich and alive the image.