quite neat details at the dust cloud. maybe the textures came out a bit too obvious, but not that bad. there's a good depth after all!
you have done a good job on the composition. maybe the brighness of some colors takes out of balance the piece, but that's how you wanted them.
the details on the planet are very good, but doesn't suit on the concept. i mean, that would look much better if all of those ships (right?) weren't pointing all around. that just seems out of place.
but a very good piece in the end! congratz