<SPOILER ALERT!>
None of you mention the fact that it was Penelope's voice saying "open your eyes" at the end. It makes you think because, was it or was it not a lucid dream? If not, what was it? Did he just wake up from his coma at the end, or is he still stuck in it....
The movie does make you think, but you do have to put a bit of effort into it.
-j