Some really quick random sketches, all painted except for the city below in the first sketch, was trying out with different photos, and the texture on the door of the 2nd sketch, i got it from cg textures.
Very nice! This has the classic Sci-fi multicolor lighting and detail with black as the overall tone. You create some classic Sci-fi renders with lots of complex shapes, detail, colors, lights, and designs. High in technology and a great sense of speed, curves, and action. I really like your renderings.