Damn, too bad FloaterTWO didn't use hi-res tex I made. Low-res throws itself into eyes. Nice composition, tho if I were you I would not overdo contrast so much and use more lamps instead for a more dramatic darker look.
Don't have it saved sry, but I can write some tips. For lighting use a lamp with a regular round sprite selected, outside of frame. Point it at your scene and move it around (use camera tool to preserve the shot and move around). Lamps create more solid shadows and also add more ambient and dynamic lighting to the shot. In my "Come back" shot I have two lamps. One over top (dark-cyan) and one behind the guy (purple). The closer you bring a lamp to your object the brighter light becomes. Also the higher your cross at the colour pad to the top, the brighter your lamp will be.