Nice use of natural backlighting and the avoidance of silhouettes. However the dog's face is attracting my eye and there's just a hint of its nose to see. I like it the more I look at it.
very out of focus, and grainy. there is also a lot going on in the background that is bothering me (like the curtain and the blanket crumbled on the bed)
This would be better if Leo were in focus. And though the challenge was to use backlighting (which you did), you can add some light in the front or to the side to give Leo a little more detail. He looks like a good guy, your Leo!