Looks nice! only, try making the wall a bit dirtier. The pipes look great, and its looks kinda weird to see such rusty pipes on such a clean and perfect wall. Also, since there are not so many difficuly models in the scene, try to put as much detail in the mesh as possible.
personally I think the rust stains ruined it for me. It looked awesome before you put them in.
If you look at stains, they’re usually in a dripping pattern downward. Also yours seem to be too intense, lightening up on it a bit would do wonders I feel.