One thing I notice...
Is that this looks like either a decal or paint on an already painted surface. Now before you go "well duh..", if you haven't already, I was going to point out that this is a nice graphic, but is it supposed to be as old as the wall that you painted on? or is it supposed to be recently added?
If this is supposed to be as old as that peeling wall, you should either erase, or make it very transparent where the base coat of paint on the wall has peeled away, so that it looks like your decal/graphic has also fallen off the wall with the base coat. If it is as old as the wall, you should probably fade the colors a bit, make the white a little more yellow, like the wall since the wall was probably white at one point in time, and make the black a light gray to represent the fading.
If this is added post base coat paint peel, you should mess around with the blending options or burn tool / dodge tool to give the decal some depth where it is placed over the peeled spots of the wall.
I'll give this a 9/10 and a 5/5 because the design is great, but it just doesn't match the wall's condition. This is just my opinion on how to improve this, so you can take it or leave it, but regardless of what I think you can do to improve it, your design is good.