It's rather hard to make out any detail on the character's face and the black on the legs looks like part of the background, maybe replace that with a dark red?
The ground looks very good, but I would think a programmer if actually making this a game wouldn't want to waste so much of the picture with a dark grey fill that isn't a gameplay element. I'm suggesting to add some texture or move the whole view down some.
The 'trees' look good, but the foremost one loses all lightsourcing at the top. It also looks somewhat faceted on the leftmost bit of its main trunk. Try using more of the colors in your palette to smooth that out.
The sky is okay, but you should use either more dither patterns or at least use the ones you have all the way. Currently you go from 25% dither to 50% dither to 100% and repeat that, try a 25-50-75-100 pattern of dithers.
The building looks great so far, and no real crits there, but I just wanted to say it'll look awesome with some more detail.