What a wonderful artwork! It states a proof that a fan art does not have to be just a copy of the original character's look and the style it was drawn in. The artist's own vision and style make it richer and full of personal attitude towards the subject.
What catches the viewers' attention first is the unusual and difficult-to-draw perspective. Minako and Artemis appear as the guardians of the city overseeing it even [or maybe especially!] at night. At the same time, the determination on Minako's face blends with the romantic gaze pursuing her distant dreams. Although there seems to be a bit of mess in the hips area that I find a little too flat, the effort put in depicting the pose deserves respect.
The colouring only adds up to the merit of the piece. Although the night scenery demands dim shades, the artist used a trick with the moon light, thus creating a beautiful spectrum of vivid colours where there should be darkness. Fans of the series will be pleased to realise another role that the moon plays - its referrence to the concept of the story of the pretty guardians of the kingdom situated on the moon.
As for the background, although the roof and the chimney were drawn with great care, the stars seem added in haste as the angle of their rays varies from one to another and hardly any of them is vertical or horisontal. Still, they correspond nicely with the reflections on the moon. I can also notice a tiny and easy-to-miss mistake in the drawing, which is the moon on Artemis's head - due to the fact that the same shade of yellow was used to colour the eyes, the moon seems to be the third eye on teh cat's forehead. It could be corrected easily by using, say, more brownish yellow.
The bearly visible mistakes, however, cannot be given more attention that the great skill the artist presents in this artwork and I hope to see more of such in the future. Having seen countless fan arts, I would even risk saying it should state an example to follow for all those who think of showing their appreciation to their idols by art. Don't just imitate, don't copy. It is your work, keep your own style, have your own vision. This is the key to a successful fan art.