Details, greater unity of color, and atmospheric effects finish the image.
I added fleeing figures and a sense of place to add to the drama and urgency.
Deciding to take it further, MimicMango made some pose suggestions and I moved the POV a little lower and added some foreshortening.
The superb pixel artist MimicMango on Twitter was curious what one of his mech designs would look like interpreted by me, so I did this painterly sketch.
My interpretation of one of MimicMango's pixelart mechs.