The movie Mirrormask is a rather flashy but overall pretty lame attempt at storytelling. The main character, a girl named Helena, is unsympathetic as a circus girl who is sick of her circus life. First off, if you are going to switcher-o a stereotype like that, I ask that there be more of a reason she doesn't like the circus, beyond just general teenage angst. The plot ploy of "sick mother / guilty child" is executed in a very confusing way (I would have found it more interesting if Helena really had done something to her mother), and the ending seemed like a hurried attempt to bring closure to a rambling narrative (spoiler: it was all a dream!).
Helena is never quite sure of her quest, which, while realistic, makes for an uneven movie. Though I struggle with these very same problems in my own writing, it also makes me more sensitive to them in other people's works. She stumbles into another world and onto a slightly-creepy (but slightly more annoying) dualistic helper / hinderer named Valentine. The lack of a clear path makes it hard for there to be any "ah ha!" moments of realization. To me, there ended up being more "so what?" moments. The world itself was hard for me to get to know and care about, as were the characters in that world, so why should I care that the main character (who I also don't have that much emotional tie to since she is pretty whiny and flighty) decided to help the people? At one point there is a connection between Helena and Valentine, that was supposed to be a big deal (friendship breaking an evil spell) but I was like, why are these two friends? Eventually, after a convoluted series of hints and puzzles, Helena gets back to the real world, and I guess, saves her mother and the fantasy world.
I know I was slightly biased in watching this movie, since it was compared to "The Labyrinth" - which also had contrived plot twists and a bitchy MC (and David Bowie, but that's beside the point). But the story of the Labyrinth had a goal - get the child. I found Mirrormask, with the threat of encroaching shadows, to be much more akin to "The Neverending Story" and it's creeping "Nothing" - but again, that shouldn't really color one towards a movie. As has been pointed out to me, all movies need to be taken in their own right and not compared to one another. But I can look at The Neverending Story and see the characters of Atreyu crying out as his horse gets sucked down into the swamp and feel a real connection to him. I can see a real threat as the possibility of failure is ever-present, whereas peril seemed to be missing, or watered down, in Mirrormask.
Finally, I must also admit that I watched the extras on the DVD which also probably effected my opinion. They stated quite clearly that the studio wanted a movie that would sell like Labyrinth and The Dark Crystal. Which leads me to believe that Mirrormask was rushed (further research shows that it may have been written in about 3 days) and too crammed with "fan service" elements (like those disturbing cats with human faces and characters I am sure they hoped would make collectable figurines) to be taken seriously. It is a pretty movie, but the characters and story get in the way of that.