To begin, this kinda looks like you combined the Grendal's mother (Beowulf animated movie) with the Prometheans from Halo 4. I dare you to say otherwise.
Now, that aside, my initial problem is with the back arm. It's very awkward. The arm itself looks too long compared to the other arm and the general position her body is in. Lowering the shoulder a bit and shortening the arm should help it look a bit more natural (I know the irony in that statement, sue me). The legs are also a bit weird. The way the hips are positioned, it seems like they're roughly at the same height. That means the back leg should be bending at the knee, which it looks like it's straight, and it'd be kinda awkward holding your leg like that in that kind of pose and maintaining balance. The eyes on the right (from the viewer's perspective) are too close to the center of the face when compared to the other eyes, and the head itself looks like you're trying to turn it but still have it look dead on which is confusing aesthetically. The breasts, I can't much complain about, but the placement of the right... circle?... is a bit off. Looking to the other breast, it should be a bit more to the center. Lastly, the tail looks like it's coming from her side, not her back. A bit of color adjustment, maybe lowering it, should help better show the placement.
Onto things I like: the color. The coloring is very nice and clean, and on closer inspection, it does give a sort of "aged" impression. Kinda like old stone or chipped metal. Either way, I love how you colored the piece. I also personally like the hair. Very nice touch. The background is stunning too, helping add to the overall study of the piece in that it really feels like something was sleeping in a place untouched by others for a long, long time.