If should say in one sentence what makes the difference between a good photograph and a great one, then I'd say that "a great photograph is one where you see more than what is represented".
This is why I think this is a great picture. What you see is quite simple and easy: two arms on a dirty wooden floor and an old wooden door, that's all, and here's where the good part begins.

Where is the person? Why is he lying there? Is he dead, or just grieving? Did someone lock him into that place?
The answers are up to the viewer.
I can already see my own interior thriller playing in my head!

From a technical point of view the picture reveals great craftsmanship. The lighting and the use of depth of field, give the picture great atmosphere, and drive the focus on the hands. The desaturated brownish colours exalt the sense of decay and dirt of the setting. The slight tilt of the camera give it a subtle sense of unbalance, suggesting something dramatic has happened.

I can't help but give this photograph full stars on everything.