I think this movie is really under-appreciated.
First off, I loved the cinematography and style that is typical for Zack Snyder. The opening scene is something I will always remember, because I was so impressed by the beautiful way it was filmed.
The story, although it might not be the strongest one around, was very different from what I've ever seen. The combination of reality, alternate reality and imagination was very inspiring and well-executed, if you ask me. Especially the video game-like elements were a nice touch.
The soundtrack was pretty great as well. The theme song, sung by Emily Browning, who also portrays the 'main' character, was haunting and a great choice (sweet dreams...).
Overall, I was impressed by this movie and hope others will appreciate it as much as me. :)