A Few Theories... (SPOILERS)

(SPOILERS AHEAD)

Great movie, very thought-provoking. There were a few things that stuck out to me:

First, I believe that the theme of the story has something to do with Whitehead taking the place of O'Neill, or the two characters becoming one. They represent a variety of opposing ideas (O. is demonic/devilish while W. is Christian, O. betrays the Master while W. stays loyal, O. is motivated by power while W. is motivated by religious faith, etc.) There is a lot of dual imagery throughout, especially during the freak-out scene (O's face is intercut with W's so rapidly that they look like one person). At the end of the movie, W. puts O.'s outfit on, symbolically taking his power.

Second, I have a theory about the black circle that W. sees in the sky. His vision could actually be a premonition of an experience he has later. Almost at the end, W. finds the scrying mirror that broke earlier. He picks up the two halves and holds them together in front of the sun. From his perspective, this would resemble the black orb that he saw before. It also suggests the theme of two things becoming one.

I have no idea what these details are supposed to mean, but they seemed important.