The pencils should be lined up with more precision, and although you cannot see the other colors, it would be better if there was an even progression of grays among them.
I like the way you compsed this to draw the eye to a focal point. I would have liked it more if the red crayon was in the place of the white one in the upper left corner.
for me this one is one of the greates in the challenge. Nice sharpness, nice black and white, really good compostions and subtle use of the desaturation - 10 This one should really win!!