If you look at this painting in real life, and from close enough, it will seem completely abstract to you. The title give an initial hint, but you see the portrait only from far or from the lens of a camera.
The painting is made with a very think layer of paint, mostly of dark shades. The lighter side of the depicted face seems to have been obtained through scraping out some of the dark-shaded paint to reveal other shades underneath (we are assisting to a process of painting that it is inverted compared to how artists normally paint: instead of adding colors, Leroy is taking it out). If you look at the painting from the side, it really appears as a landscape, with valleys and hills. The texture of it is similar to the texture of wood, that brings us back to nature again.
During the same period, in Paris (where the artist lived), the Nouveau Réalisme was taking place, and the idea of going back to rough materials, to accumulation, to found objects was very present. This artist remains unique in his way of painting, and whoever loves materiality paintings, you will love it!