It’s looking fantastic, but since you did ask for crits…
(Take what I say lightly, because you can see how little experience I have!)
But, I would say that perhaps the sky is too light, especially the bit of clear cloudless sky. What CodeNothing did with this was also good.
I’d also say that the image is too crisp, especially in the distance (even maybe on the central floating thing)
It would be nice to have something to break up the buildings a bit, especially on the LHS. The lighting on the RHS does this well.
Add in some life. I realise this is a matte painting, but for presentation purposes, it would be nice having spaceships flying around (or something).
Not that I would ever have a hope of producing anything half as good as that!
George