I really like this piece. I'm not sure, but I'm given the impression the sky is supposed to make a face overlooking the guy? If not, then I suggest making the moons a little different, perhaps have one bigger than the other. Also, since the moons are quite a bit away from each other, one would be slightly more into a phase than the other.
But overall, since I see you adding in a third UFO, I don't think this is going to be some big face. I think things are really out of place and some things should be adjusted. The UFOs don't look right directly over the moons. It just seems like there is one of each thing on each side, being piled on top of each other. I think it'd look a lot better if the layout of the scene was changed.