Looks pretty interesting, Mike. Maybe try to add more depth to the trail of the comet, and also, work on the background. Maybe add some more stars & planets or something?
The colors need to be matched and/or complimentary to each other. If the red if suppose to be a trail of fire, well make it look like fire. (Fire stocks, try some of the Resurgere packs @ deviantART). The blue is too apparent. Try lowering the opacity on it slightly. Interesting piece. Just work on your colors and blending.
