Plot hole: In the first scene Alice hears on the radio that three teenagers had been murdered in Haddonfield just down the street from where they live. Yet a few scenes later, the sheriff finds out from his deputy that 3 bodies have been found. Wouldn't the police department know that before it made its way onto the radio news?
Suggested correction: When Alice is on the phone, she tells her friend she can hear the sirens so the police knew about the bodies. As for the sheriff, he'd been busy with Loomis all night. He might have heard about the bodies in the house but figured the other policemen could handle it and that way he could continue helping Loomis. The main reason the deputy came to talk to him, however, was to tell him that his daughter was one of the victims found.
Halloween II was a troubled production, and the scene with Alice was added during re-shoots. Note that the previous scene with Mrs. Elrod also includes a news report about the discovery of the bodies. I've seen no concrete evidence of this, but I've wondered if the scene with Mrs. Elrod was shifted closer to the start of the film, and was originally meant to take place after the scene with the sheriff.
Good theory, but the deputy runs up to the sheriff and informs him for the first time of all three bodies.
Plot hole: Laurie is pounding on the door and screaming for help. But Loomis doesn't hear her for a full 20 seconds? It even shows him standing 30 feet from the door and he doesn't come running until Laurie has screamed for 20 seconds.
Plot hole: Early on, the TV in the Elrods' house is showing a report (corroborated by the authorities) of three bodies being found in the Wallace house. However, later on during the Ben Tramer accident scene, the deputy rushes up to the sheriff to inform him that three bodies were found (including his daughter Annie).