I think a great deal of the reason for the 56% is the way the film was marketed, and the expectations of the viewers going into it. Really, that's the real twist of the movie: that it's an art film dealing in metaphor and symbol, rather than a horror flick. Oh, it has some creepy, tense moments, absolutely, but that's not really what the film is about. David and I both liked it. I suppose the English major in me eats that sort of stuff up, so maybe I'm the target audience, but I appreciated the theme of innocence lost at the price of awareness.
I suppose it's all obvious after you know the secret, but even though I had a pretty strong hunch of what the secret was at the outset, it didn't hinder my enjoyment at all. In fact, I'd say it heightened my sympathy for the characters a bit. I also utterly love a good dose of rich atmosphere, and the movie has that in droves. It's something I look for in video games, as well -- immersion goes a long way with me.
The only real criticism I have of the movie is that some of the actors seemed to have some problems with the stylized speech of the script. Otherwise, I found it entertaining. Not his very finest work, but thoughtful enough for those of us with artsy friends to enjoy a discussion about it over tea at a local cafe. I enjoyed it. Change your expectations of it being a monster movie (it's a horror movie, but on a mental level, rather than having big salivating aliens jump at you), and you might, too.