I'm not to sure about the first one. I don't like the planet on top of the city, That one would look better with probably having an explosion in the middle of the city or something. Is the second just a photo? because that's what it looks like. The third looks pretty good.
The first one makes no sense. From the way you set it up, the planets would be colliding into each other. And it's just an awkward angle. And are those planets from Resurgere stock packs? Lol.. Try making your own... EDIT: And stop saving as .png. It's completely worthless and you'd be getting the same quality out of a jpg but a smaller file size. The third image is over 1MB... most people won't even bother looking at these on deviantART because of the loading times.
