The Cutie Unmarking

Ok, first off, this piece is really great. You did an awesome job and since I'm a random guy from the internet, who hasn't even enough talent to draw a stick figure I'm going to tell you why. <img src="e.deviantart.net/emoticons/b/b…" width="15" height="15" alt="" data-embed-type="emoticon" data-embed-id="366" title=" (Big Grin)"/>

The pose, oh this pose. It's simply awesome. Starlight feels really dynamic and dangerous in this picture. That’s how a villain should feel when you first look at him/her.
The background is also really good. You managed to make the cave of the cutie mark vault recognizable without using the vault itself in the picture. Like this you make the background itself subtle, so it doesn't steel attention from Starlight, yet at the same time, you manage to make the watcher remember the scene itself. Perfect harmony if you ask me. <img src="e.deviantart.net/emoticons/s/s…" width="15" height="15" alt="" data-embed-type="emoticon" data-embed-id="391" title=" (Smile)"/>
Colors, mane, tail and magic are all top notch and leave no room to criticize.
But the absolute best thing about this is her face. I love how you draw eyes and these are just so incredibly gorgeous, I could stare at them for hours. These two beautiful eyes together with her expression really nail it down that she thinks she has won. She has everything she wants and even an alicorn can't stand in her way.

Résumé:
This is an awesome picture of a great villain and it does that villain justice.
As Rainbow Dash would say "You ... are ... so ... awesome!"