Continuity mistake: When Cheryl is running through the woods, she is wearing slippers that stay on up until she reaches the cabin door. However, in following shots, she is shown barefoot, and when Ash opens the door her foot is dirty as if she'd been running barefoot the whole time. (00:28:05 - 00:29:10)
Visible crew/equipment: On the GoodTimes DVD release of Halloween 2, just after Dr. Loomis blows up the hospital room the camera switches to the hallway where Laurie is running away. The explosion comes through the hallway and you can see the right side of the hallway shaking - this shows that the wall is a studio set wall. You can also see wires behind it and the wooden supports that are holding it up. (01:25:30)
Revealing mistake: Just after the scene where Mark is killed, there's a shot of Jason's feet as he opens a screen door and walks across a dusty hardwood floor. As the dolly pulls backward across the floor, you can see the camera's roller marks in the dust. (00:59:10)
Visible crew/equipment: In the scene where the bad scanner is trying to kill the good one using the telephone line, when the good guy turns it back and blows up the office/lab at the other end, one of the scientists is blown back through the glass by the explosion. In the shot from outside the room, it is easy to see the cable pulling him back. (01:22:55)