When Kiefer Sutherland’s character says to Amy Smart’s character “Hey cis”, the film is unlocked as a trans allegory. Sutherland plays a trans man evidenced by his continual taking of pills and his recent alienation from former friends who seemingly can’t accept who he is. His obsession with mirrors is a reflection (!) of his anxiety about his appearance post-transition. Ultimately Sutherland accepts himself by metaphorically killing the oppressive Catholic Church and literally fighting the demon in the mirror. He realises that it is not himself but the world that needs to change: the whole world appears backwards to him at the end.
A deeper, more interesting reading than this film deserves.