I'm actually more into space art when it comes to critique but since sci-fi is also part of my speciality, it should do.
You have my respect for actually drawing the whole image traditionally since I've never been quite good in it myself.
The inspiration in District 9 is obvious and I think that you achieved what you wanted. Perspective and depth is really good and brings image to life. Blurred clouds might feel a bit mediocre for someone but I think they actually further enhance the depth.
Lots of details put into the ship are a plus, but the rest of the image might also have that amount of work - buildings are okey, but some life into the surroundings would do a lot - I know that you were inspired by D9 but some sci-fi city traffic can do miracles.
The ship is definitely the center of focus. What I think might look even better though, is a non-central position of the ship - moved a bit more to the left (maybe it would require a wider image) would reveal more space for some further background/surroundings details and maybe even give even stronger sense of depth.
All in all - a good piece (not really original, but hey - you were inspired) and a deserved from me.