Hey, Mush.
--->CRITBARPHHHHHHHHHHHH::::::::
I like this, to the 2nd, possibly 3rd, power.
The sky is the focal point, it's very visually powerful . . . uhh as far as focus I mean. Compositionally it seems to "crush" everything else; overpowering. But it's a toxic world, so the sky rightfully has some priority there.
Your cloud texturing technique will really determine the sky's final worth. Clouds can be tough. Will they parallax/scroll? Gotta make 'em tile seamlessly then. Don't forget.
If sprite is placeholder, and wrong size, just arbitrarily scale him up a bit so he's a better representation of scale, etc.
Bg buildings are very rough and ill-conceived. Looks like Egyptian pyramids and random towers; nothing that sell the "industrial world" theme at all. They just . . . make you wonder; distraction.
Is sprite running along a bridge over water? Why are the areas under the bridge lighter. If the water is that disease-ridden then you may not see such a strong reflection of the bridge's arcs. I seem to associate clear clean water with high reflectivity. Imagine a non-glossy matte surface to the water.
Give the water foreground some floating trash, toxic barrels, debris, etc.
Use the illusion of volumetric fog/haze to illustrate toxic smoggy polluted air. Transparent foreground smog clouds floating by? Why not. Transparency isn't a crime.
The bridge is crazy-boring. Give it some life, some details. Make my eye not want to skip over the whole thing at once. My eye is pulled to the sky and those bg pyramids.
Go for a mechy techy over metallic, sorta steam-punk but not 1800's, style where there's metallic gadgetry where you wouldn't expect because technology, in this world you're depicting, is over-utilized, and it therefore everywhere. Visually, this gives your game some extra neato details, and let's admit, random techy machinery stuff is fun to draw.
/stomachdepletion