Some of the great aspects of this picture is the coloring. The background clashes with the character, causing her to appear brighter and happier. Now, this is really unique. Usually Nightmare Moon in shown with a dark background reflecting her evil personality. But here we've got pretty pink. Interpret how you will, but I think it makes her stand out a lot more. The reflection on her eyes is really incredible, but the shiny dots all over make it look like she's just emerged from water. It gives her mane and helmet a very gel-or-jelly look. All in all, it's really a very beautiful piece. Keep up the good work, and remember you can always improve.
My biggest gripes with this work is how unfinished it is and how confused the shading seems to be.
I'm having trouble to recognize the figure as either abstract or realistic. You can go either way, just remember that going realistic requires you to fully capture that feel of the character being right in front of you and going abstract provides you with the freedom to combine elements of realistic paintings that don't usually go together.
It largely seems as though the artist had been experimenting, which is perfectly fine, but not at all appropriate when you're asking for a critique. They should really add a touch more detail to the painting. Because that's what people largely pay attention to, and what would likely make them come back to take a closer look.
KP, you're definitely good at leaving an impact: your style is interesting and refreshing; you're even one of the few artists whose work I'd still enjoy even without its MLP aspect; just have all this in mind the next time you draw.