It's like you took trendwhore, and inflated it.
it's way overkill with the stars and planets. you could have had a much better effect just by having Ren and the planet she's holding enlarged and put slightly off center with some text, and hints of smaller planets in the background. the first thing i thought to myself was..."is this an anime wallpaper?...oh, there it is."
it doesn't blend nicely, and the sense of space and depth is completely off. is she really tiny and in front of the planets? or is she really big and behind them? or was she just slapped on there?
i think you should rethink the concept of this one. sometimes it's better just to stop and take a look back and ask yourself "what is the most important part of this wall" and focus on that and accenting that part as opposed to burying it with effects like you did.
simple can be even more effective than complex. keep that in mind.