Good use of black and white to emphasize the tonal range and play of light and shadow. I like the natural light illuminating his face, it gives it a somewhat 'wonder' feel to it. The only nitpick is what I think is his hand opening up the curtain. It's not clearly defined as a hand so I partly wonder if it is something else, and also it seems to be 'growing' out of the top of his head, which makes it somewhat of a distraction.
great portrait - love the light on the cheek, jaw and eye. obviously the shot is outside the challenge stipulation (you'd have a hard time convincing me that the subject of this shot is the view from a window), but I'd guess anough people will have bashed you for that already. My mind questions the cropping - but my eye finds the compositional balance very effective.
of all the "kids in windows" i like this one the best. i cant really put a finger on it. the framing is well done, and he looks well dressed. perhaps the texture of the drapes...i dunno. very nice.