The background. It looks like a foreground, somewhat flattened. I’ll use more contrast in the foreground, some shadows, more saturation in the colors. I would paint areas and then wipe away the paint to leave traces, sticking primarily to the same main colors of yellow ochre and rose madder. In the first draft, the dude looked kind of dopey. Now he looks crazy sneaky.
When I took the photo, my camera used red eye reduction. You know your facial proportions are right-on when the camera mistakes it for a person’s face.