The sense of "moment" is present in this image and the obvious character being captured is full of humor and a sense of fun. Technically, it seems a little dull which may be the lighting conditions - the author might have wanted to use a little more saturation to correct for the washed out effect. The use of the vaguely detailed background is a plus. From an artistic standpoint, the subject is too offset to the right to be truly effective - a little more towards the center would have been a huge plus. Still a worthy entry into the challenge, it just falls short of being outstanding.
This is a wonderfully candid shot so it kills me to say that it's a little bright. I don't know how much PP could have been done to lighten it just a tad without losing too much of the photo.
Note-I am not voting in this challenge just commenting on the ones that I can per request in the candid scores forum.