Sci-Fi element aside, I think this movie is more an experience of mental illness
You can go with the the time loop theory or you can also go with another theory... that this is a schizophrenic experience. Obviously the main character dies, but we get to experience ''Schizophrenia'' as the viewers through the film. I think the movie theater scene in the film made me realize the film was more about mental illness. Donnie's behavior in that theater, laughing and smirking and behaving ''disconnected'' when seeing the giant rabbit and then when being asked by the ''hallucination'' to burn down a house, him smirking again. Something just seemed so... unsettling about it. I don't think this is a time travel, time warp, end of the world film - I think it's an experience of schizophrenia. Here we get to see hallucinations, layered delusions and time distortion.
share