Continuity mistake: The Halloween scenes in the movie don't match up. For example, Randy is watching the part where JLC first discovers the bodies. About ten movie minutes later in Halloween, she's hiding from Michael Myers in the closet. Then Billy gets the idea to search for Sidney, because that's the scene currently playing. Too much time occurs between scenes for this to occur.
Continuity mistake: When the killer sneaks up on Randy, Randy is lying back against the sofa. When Ghostface raises the knife Randy is lying back, relaxed with a tired look on his face. On the delayed footage when the killer raises the knife, Randy leans forward and is practically on the edge of the seat, his mouth and eyes wide open.
Continuity mistake: When the whole gang is watching Halloween, they see the scene in which Michael Myers impales a victim with a knife, which suspends him from the wall. Just before Randy pauses the movie, Michael Myers is standing and admiring his handiwork. When Randy pauses it, the frame is of Michael Myers raising the knife, which of course, happened 10-15 seconds ago.