Viewing the example image, my only real suggestion is maybe using a new layer to do some overlays? You could have a brown fog slowly creeping over everything, or whatever.
Ignore me if you hate the idea lol.
No no sounds like a great idea to me... just wondering what impact it might have on performance though, as there are already LOTS of tiles on the screen... The craters are overlays as well as the water... its animated overlaying a "sludge-looking" layer with an additive filter. Some smog or smoky residue might look really cool though! I might even make it like swamp gas rising out of open manholes or something?
I also haven't added in all the details, like burnt-out old cars on the side of the road, road boundaries, old broken trees etc... I might keep adding to the mock screen shot as I make more graphics until it looks more like the final output
Great idea though! This is the kind of suggestion I was looking for. Got anything else?