Plot hole: What exactly was Laurie Strode's plan in the teaser, when she strung Michael up over the edge of the roof. From the way she starts cutting the rope it looks like she plans to drop him, but she's seen him survive a 2-storey fall before, in the original Halloween, not to mention multiple stab wounds in H20. A fall off the roof into bushes would barely phase Michael.
Other mistake: This is a timing mistake. In the beginning of the movie, when Michael kills the first security guard, he stuffs his head in the washer. The second security guard was in the room within 30 seconds. There is no way that Michael had time to cut this guys head off, stuff it in the washing machine, turn it on, and hide before the second guard got there.
Continuity mistake: In the scene when Rudy has the last last knife stabbed through him about fifteen centimeters of the blade go through the other side of the door. About fifteen seconds later from the fitted camera view you see Michael open the door and Rudy has a large, thick padding on his back. There is no way the knife could have gone that far through the other side of the door if the padding would have been that thick.
Continuity mistake: When Nora is making her coffee from the machine you can see most of the computer screens. If you look at the one with Charlie on it you can see him walk backwards with the tripod leg pointing at him, but in the next shot,when you see the screen close up, he is kneeling down, Michael Myers catches his attention and then he stands up.
Plot hole: At the end of the movie, the fire department and paramedics arrive just after the house has been set on fire. Yet, as the focus shifts to the outside view, the house has burned all the way down (which takes a couple of hours) and the paramedics STILL have not gotten around to sending Sara and Freddy away for questioning or hospital or the like.