While I hold little to no gravity on Deviant Art at this time. I look to help you improve and better your works.

To begin, what you have is fantastic. I feel it is nearing the border of phenomenal.

Color: Your use of color is very well orchestrated. While some tend to want to overdo colors and appear anxious, you have stuck to a palette of believable and realistic colors. Your selection gives a gritty and honest hint at space combat.

Lighting: The lighting is also well done in terms of realism to the ambient. However, it seems somewhat dull, in comparison to what it could be. I believe your piece would benefit from a slightly higher contrast in lights and darks. Despite this, it all depends on implied positions of elements such as stars, planets, and other ships not within your work space.
Purely from an outsiders perspective, and as one who is interested in game concepts such as yours, it is more pleasing and drawing to the eye to have more powerful lights and darks.
(A possible solution might be to tone down the brightness of the "4N4C" because it feels somewhat unnatural. However, if these characters were intended to be electronically lit up as a feature of the ship, you may wish to find a way to add a subtle glow around the characters on the ship's hull.
Another way to strengthen the lighting might be to add a strong silver lining to the rightmost border of the ship to emphasize the sun's/star's reflection off of the planet below. This helps give the planet more presence and creates a "shock and awe" effect to viewers.)

Organization: While what you have is good, such as the incorporation of a planet and the implication of a ship somewhere above the ship this piece is centered around, there is always room for improvement, or addition of other elements (granted, you are allowed/have time to add more elements).
Being that the ship pictured is alone, it presents the problem of emptiness due to the size of your vessel and vastness of space. In these cases, the ship can be made to take up more room of your workspace, or you can use subtle techniques to make your ship seem larger without actually expanding its presence in the workspace.
(Possible solutions to make the ship feel bigger might be to add ships with which to contrast size with, such as fighters or smaller vessels. In the events your game is based on the idea of a single ship traversing space, your piece would also greatly benefit from placing the enemy ship in view somewhere, whether as a silhouette in the distance, OR as a shadow being cast on your current single ship.) Overall, the placement of each element in your piece is good. But it can become great with a few adjustments (Easier said than done, understandably).
You may want to play around more with where you can place the ships, how close or far you are from the ships, how dominate the planet below is, where implied light sources are, and so on.

I hope this critique was of help to you. Best wishes!