The characters blend into the wall too much.  I can't even crit it because I can't see anything. 

everything said by anlina..

what i don't get: are the 2 guys (and the leaves or whatever it is) floating in front a wall?

Neat concept but the contrast on this is so low, your characters just disappear into the background. Nothing wrong with doing a greyscale image, but you really need to work the contrast.

I also find the composition of this really unappealing. You have these two tiny characters near the bottom corners of your image, a horizon that cuts through the centre of your image, and a big empty sky. I'd really suggest looking up the rule of thirds - applying basic composition rules would really improve this piece a lot.