Continuity mistake: When Lily breaks into Roy's apartment, she unscrews two small light bulbs in the fixture next to the front door, throwing that whole end of the hallway into darkness. When Roy returns home, he opens the door and the hallway is brightly lit again. (01:32:45 - 01:34:15)
Visible crew/equipment: There is an entire scene done with a full room camera shot, and for the entire scene you can see the boom mic at the top of the screen.
Continuity mistake: When Lilly gets up to leave after killing Roy, her legs are covered in blood. In the next shot, there is no blood on her legs as she descends the apartment elevator. (01:44:45 - 01:45:25)
Continuity mistake: Mia is strangling Lily in the motel room, quite convincingly. When Lily shows up at Roy's apartment, she wearing a red scarf, presumably to hide what should be vicious bruising around her neck. When she removes the scarf, her neck is almost completely unbruised. In the time it took her to drive from Phoenix to L.A. (7 hours or so) her neck should be black with bruising. (01:39:10)
