This stuff looks great as a start. The colours create a good atmosphere.
You can improve the textures etc but before you go there I think roughing out some mid-ground would benefit you.
This could be things like rock faces, structures, fences, conveyer belts, light poles, futuristic trucks, big storage tanks, pipes etc. etc.
Deciding exactly what the place is will help ideas to flow.
You can always have multiple areas for other ideas anyway.
The top screenshot looks like it can use some stairs between levels, elevators (e.g. with warning light), downlights etc.
The background on bottom screenshot is good for what it is but the endless shipping containers scattered randomly looks odd.
You can draw more refineries in the background, domed living structures etc. etc.
Will there be sloped platforms?
Planning on going inside any of the structures?
Will we be going underground?
The last structure is much lighter, and imho wouldn't work well with the character you presented. Imho, something in-between -- half the width of the 1st picture, but same scale, would work best.
The second image looks like separate scaffolding, not part of a structure.
But yeah the beams are a bit thick in the first image. They also block out a lot of the background.
I'd go thinner on the vertical beams and thinner again on the cross-beams (like under the bridge bit).
The perspective is also confusing leading to an origami appearance.
Seeing the beams behind like that suggests we should also see a bit of the side of the platform, and the railing on the far side of the platform.
Either do this or don't have that perspective at all.