There is a lot of good in the character drawing and the color choices there, but I feel like this piece is fighting with itself. The background is doing a lot to muddy what we're looking at. The diagonal angle of the the bars creates a lot of visual action, which isn't a problem, but the way that the character's arm are following the direction of the bars makes it look to be lost in the direction. Adding to the problem is that between the background and the character the values are very much in the same area so there isn't enough contrast to push the character forward and the background backward.
I would recommend darken the tones for the background or the shadows on the character more to create more contrast. Or going for a background that doesn't have such stark lines, that way the graphic shading on the character can be pushed out more against the background.

On another note, I really like the way you did the linework, the bit of transparency in spots really does a lot to add character and interest without sacrificing the boldness of a black outline.