Wow. Even if it is only gray, nice shading on that middle rock for your first prototype! Some extremely good maps simply have gray shading if you view their untextured versions; a colored texture takes care of the rest, so go change it to something 1337 (easy in MM; central-top).
I've never played Leo's inf. server so I don't know about gameplay tweaks. Might want to change the bland background colors and throw in more scenery, possibly sandbags and boxes (lay colliders over them to give them an easy bullet-blocking effect).