Continuity mistake: When Michael first gets his head cut off by Laurie the eyes of the severed head are clearly wide open. (in H20 and in flashback scene) Then when they remove the mask from the head, not only is the mask suddenly and noticeably different, but the eyes are now closed.
Continuity mistake: When Rudy is in the kitchen, he tries to open a door but it's locked. After Michael pins him to that same door, he opens it right up and walks through.
Continuity mistake: In the garage, Sara falls into a cart with equipment on it. It tips over easily yet the equipment lands on Sara's leg and she's unable to move.
Continuity mistake: Halfway through the film, we see Michael Myers walk into a room immediately followed by another Myers. Both are dressed nearly identically in a blue jumpsuit. But as soon as the first one turns around and we learn it's actually Freddie, the shot changes to Michael and back to him and he's wearing his jean jacket, seen in the rest of the movie.
Factual error: School emails are .edu, not .org.
Continuity mistake: When Michael Myers has Sara cornered, he rotates the knife in his hand so the blade is pointed down. After being knocked backward by Freddie, Michael advances forward and once again rotates the knife to point the blade down, yet he never changed it back.
Plot hole: Bill was killed in Judith Myers' bedroom, but his body was discovered on the stepladder leading to the attic. Wouldn't there be a noticeable trail of blood leading from the bedroom to the attic? Michael might hide bodies but he doesn't clean up after himself.
Continuity mistake: Near the end of the film, Deckard is communicating to Sara's handheld device where Michael Myers is in the house. When Deckard tells Sara to "GO NOW!", the text has changed from small digital text to large bold font and the screen has changed from green to white, similar to a large PC monitor.
Continuity mistake: Freddie has all the cameras cut when they find out he's a fake Michael Myers. When the kids complain to Deckard about it suddenly going offline, they tell him to bring it back. Deckard types at a fast rate, yet not only is there no dialogue box for text to be typed in, the screen remains the same.
Visible crew/equipment: There's a cameraman visible when the two guys walk into the house party. He doesn't belong in the scene and is filming.
Continuity mistake: At the Myers house when the guy with the black jacket is lighting a candle he uses his right hand then the left.
Revealing mistake: In the H20 flashback when Laurie cuts the head there is no blood from it.
Plot hole: When Busta Rhymes says "Cut the camera. Cut the camera" when he is attacked by the kids. Who is turning all of the cameras off at once? Prior to that scene, he runs into the real Michael Myers and has him go into the garage with Nora to "help her ass out." If he did, then I doubt she would be able to turn it off and on.
Continuity mistake: When we see Michael in the flashback with the security guard, he has on his mask from this movie, when it should be the Halloween H2O mask.
Continuity mistake: Jen's head lands at the bottom of the stairs. Later on in different scenes of the movie, it's obviously not there anymore because of all the running around downstairs and upstairs. Yet it's conveniently where it landed the first time because we see it on the monitor in the garage.
Continuity mistake: When Michael pins Rudy to the door, he uses the two knives that Rudy had in each hand. One of the knives goes clear through the door and out the other side. Michael then gets another knife from the drawer and it too goes through the other side, but the first knife that went through is now gone.
Audio problem: After Donna is killed you can hear her still screaming.
Other mistake: When Donna is in the basement by herself, she sees a picture of Laurie cut out of a newspaper. This is a picture of her from Halloween (1978) when she was waiting for Annie to pick her up. So where did it come from?
Continuity mistake: In the garage Sara falls down and a piece of electronic equipment lands on her. She acts like it's so heavy that it has her unable to move. Yet when Freddy comes to her aid, right before he lifts it off, Sara starts to get up on her own.
Answer: At first impression, Laurie was catatonic not only from the shock of killing an innocent man, but also from a lifetime of being chased down by her murderous brother. She obviously knows from past experiences that nothing she does (including faking her own death) will stop Michael from finding her. It is later revealed she has been faking her mental issues (think when she has been hiding her regular meds in the raggedy Ann doll) and is committed only to stopping Michael, no matter what the cost. She may have also been trying to protect her son and the only way to do that is to allow herself to be institutionalized in order to lure Michael there.