Visible crew/equipment: In the scene where Banderas knocks at the hotel door of Romeyn, you see the camera crew reflected in her sunglasses. (00:56:16)
Continuity mistake: When Rebecca Romijn's counterpart pins her suicide note to a picture, it changes from slanted to the right, to slanted to the left and back to the right again in several shots.
Continuity mistake: In the scene where Rebecca Romijn keeps her black-haired counterpart from killing herself, initially, her right eye is white, but in later shots, it is very red.