28 colors are a lot for this little wall, I agree. Some lines are not very iso-like (the ones on top of back bricks). Iso is often like a puzzle. Every single pixel has its very own place, the trick is to find it ;)
Well you should expand the shadow to accommodate the walls that are not facing the sun. I have to ask why are your walls purple?
Good feedback, I wasn't really watching my color count like I should. I'm sure I can pare it down quite a bit, and fix those back lines.