The premise of the movie is quite interesting, and well developed. The special effects are top-notch, the sets very immersive, the camera moves just right, and the soundtrack solid.
However, the story is weak, the suspense even more so, the dialogs are no more than minimalist, and the characters very shallow, but well acted.
All of that being said, it's still excellent entertainment, especially on a large screen. The 3D is very well done, no panning at all. I saw it in IMAX, and I wasn't disappointed.
Want your action fantasy fix? That's what it's for.