Those are pretty sick, only problem I have is part of kobe's head being chopped off in the bottom left
Work on your cropping. In both walls, the figures look distorted and parts are chopped off. Also, a more creative text could have been used on the Kobe wall. BG is also too simple for my liking. Just my 2 cents.
There is to much going on in the Kobe sig. Try giving it one main focus instead of a bunch of Kobe pics thrown around a BG. Like Aznx said, you seem as if you are just starting to get into making walls, so keep trying. Good effort.