Continuity mistake: When Pamela Susan Shoop is being killed by Michael in the spa, the towel is tied arround her upper chest, then the towel falls down, revealing her breasts. In the next shot a split second later the towel is back up at he upper chest.
Continuity mistake: At the end of part one, Laurie's stab wound was just a streak of blood and none on her shirt at all. When they bring her out to the ambulance, there's now a lot of blood on her shirt and streaks of blood on her arm. (00:13:20)
Continuity mistake: After getting out of the car, Laurie is on the ground beside Jimmy's car outside the hospital when she sees the Marshall's car pull up. When Loomis tells the Marshall he ought to handcuff him to the wheel, if you look, Jimmy's car is still visible in the distance, but Laurie is not in that shot.
Continuity mistake: In the scene where the boys ask Mr. Hunt about Ben Tramer, Mr. Hunt says that "it's just a little past 11." Following this up in the next scene Bud lures Karen into the room to kiss her and wish her Happy Halloween. During this scene, as Bud reaches up to kiss Karen, his watch is clearly visible and shows the time as 1:00.
Continuity mistake: The flashing lights on the front of Bud and Jimmy's ambulance change places as they pull into the hospital driveway. They go from either the side of the hood to the front of the bumper.
Continuity mistake: When Michael falls off the balcony, he falls into some green grass and a garden is next to him. Yet in the original "Halloween", Michael falls onto the ground with barely any grass around him, just a dirt patch and no garden in sight. (This is explained because they reshot the ending to "Halloween" 1.).
Continuity mistake: Michael comes into Laurie's room and stabs at her bed, only to find pillows had been placed there. He then walks out and leaves the door open. When Jill returns from checking on a patient, the door is now closed and she opens it.
Continuity mistake: When Michael walks into the old couple's house, NIGHT OF THE LIVING DEAD is showing on the television. At that point, the film is just beginning, with Barbara and Johnny first pulling up to the cemetery. Much later in the film, the security guard is also watching NIGHT OF THE LIVING DEAD on television, and it's the scene where the cemetery zombie is attacking Barbara in her car. This is no more than ten minutes later in NOTLD, yet it's way more than ten minutes later in the evening of HALLOWEEN II.
Continuity mistake: When Ben Tramer gets hit by the police car and trapped in the explosion, you can see his body slump forward onto the hood of the car. In the next shot, he is pinned fully upright.
Continuity mistake: The front door on the Doyles' house is different from the one seen in Halloween. You can see this when Dr. Loomis leaves the house in the beginning of the movie.
Continuity mistake: After Laurie wanders into a hospital room and unsuccessfully tries to use the telephone there are a series of shots cutting back and forth between the room and Laurie looking out into the hallway. In the shots from inside the room the telephone shifts position at one point. (00:59:01)
Continuity mistake: When Michael is stalking the hospital corridors there is a scene when he hides in the baby unit and is observing the Head Nurse berate Nurse Karen for being late again. The scene switches back and forth between a close up of the two nurses talking to a shot from Michael's perspective of them from inside the baby unit. In the close up the Head Nurse's body is facing Karen, from Michael's perspective her body is facing towards him on the other side of the nurse station. (00:30:20)
Continuity mistake: At the beginning of the movie, the front door lights on the Doyle house are on, then off, then on again in just a few different shots.