This image is interesting and I think holds a lot of potential as a graphic work.
Though no one will say it looks real, I don't think realism is necessary or the point. As a graphic work, as opposed to an attempt at photo reality, I think that you have used TG2 in a somewhat unique and inspiring way. For example the destruction of the planet while not being 'realish', is certainly exciting. The large shapes of the planet material moving away from the main body make for nice shapes and forms. This image's strong points are form and movement. And I think with a little work and research for inspiration you could make the render much stronger than it is.
A big problem with the image, something that keeps it from really working is the ring. I like the idea of the ring but its not working here. If it were my image, and I knew how to do it, I would keep the ring but make it up of smaller forms and shapes similar to the large chunks from the planet body, and only as many as were necessary to imply the shape of the ring. Perhaps Dandelo's rings (you can find them in the forum) would be a better starting point. There is also the problem of the ring reading as just a white curricular form thrown across the center of the image, its not making visual sense.
Don't go over board with detail and large numbers of rocks to make up the ring. Make it match the planet's look and that of the parts moving away from the planet.
Lastly I think that the flames are hurting your composition, as well as the placement of the planet right in the center of the frame.
After That I would try to give an extra feeling of outward motion, perhaps with a motion blur or some other simple method.
Just my two pennies. Hope it helps, if not just ignore me
