Let me start by saying I love this. I think the balance of colors and the mood you achieved is fantastic, feels like a place that I'd like to visit, despite the fact that it feels almost inhospitable. The snow and mountains are especially well done, I've probably got myself a new wallpaper now.

One of the things that bothers me, though, is it seems almost like you have a a very slight lack of direction. What I mean is you have three different man made elements in the painting, and although it's good to have variety, having singular instances of those things I think weakens the piece. You have the ship, the block of buildings, and the little structures/figures to the lower left.

I feel if you perhaps took one of the three elements out, or repeated additional instances of some of them, the piece would feel more cohesive. One thing they do well, though, is lead your eye through the piece, which is great.

The only other thing that I think stands out a little bit are those buildings you put in. I love the sense of massive scale you have, but I might put some more in to the left, or maybe some indications in front of the mountains, so it doesn't feel so much as one monstrous construction, and more like a city.

Other than that, I might indicate some lighting from the star on them, they seem like they should be getting hit on the edge at the very least, and I think it might help you tie the two halves together by bringing some orange into that side.

All in all, fantastic job dude, I really love it. My critique sort of comes down to nitpicking, but when a piece is so solid, that's really all you can do. I admire the quality in your work and cant wait to see what you do next.