• Revealing mistakes: SPOILER: When Bateman hits Paul Allen with the axe for the first time, the blood sprays on him before he actually hits him. Also the blood comes from a different angle than where Allen's head is supposed to be.
  
  
• Continuity: SPOILER: When Patrick Bateman is packing a suitcase in Paul Allen's apartment, the light is switched off in the bathroom behind him. But as he stands up and heads for the door the light is now switched on.
  
  
• Continuity: SPOILER: After killing Paul in his apartment, dragging his body through the lobby you can see the blood trail following the bag. But once he's outside flagging down the cab, the view back into the lobby shows no blood.
  
  
• Errors made by characters (possibly deliberate errors by the filmmakers): SPOILER: Bateman could not have killed Jean with the nail gun because that model of nail gun must be plugged into an air compressor for