I not too familiar with this critique system personally nor good with words in English so I made a little over-paint on the upper part. I not touched your proportions nor the shape of the forms but played a bit with the lights and shadows to make it ways more outstanding yet not overdone with effects-colours. Since I did see you try to make the distant parts go in the distance with make the toning more greyish which helps to give back depth I used this way to make over-paint. You can find it right here (and hope the link works); [link]
I am better visually then with words, hope this can help you a bit!