If it weren't for the backlight, the lion would really blend in with the background, so it really makes the lion stand out (which was the point of the challenge), so great job!
Animals (as well as insects, people, etc) are nearly always more interesting if you can see their eyes. Of course, if you can see this fella's eyes, chances are he can see yours too and maybe that's not so good! Anyway, I think the photo suffers just a bit from the profiled view, plus the obstruction (tree branches and limbs) in front. Sometimes ya just gotta be patient and take lots of shots hoping for the best one. The backlighting, however, is good. So the other things would only serve to improve the image. I'd love to go where I could take this kind of picture! Good luck in the challenge!