In the opening sequence, Marion's house is supposed to have a loss of power.  When Jimmy goes to investigate, however, the light bulb in the refrigerator comes on when he snags the beer.  If there is no power in the house, then the light bulb should not have come on in the refrigerator.

In the beginning credits, there's a picture of Laurie Strode in the Haddonfield Yearbook.  It says "Class of '78." It should be "Class of '79," however, because the film took place in October of 1978, when Laurie was a senior, so she would have been graduating in the summer of '79, making her "Class of '79."

Also in the beginning credits, one of the articles says "Lauries Strode, who survived the Haddonfield murders in 1968..." instead of 1978.

In one of the articles at the beginning of the film, during the credits, Michael Myers' name is spelled wrong. They spell it Meyers at one point.

More than one mask was used in the filming of the film.  This is quite evident as the look of the mask changes from time to time in the film.

This isn't really a goof, but more of a factual mistake, where has be been for 20 years?!? And how did he know that Laurie Strode faked her death? The film omits Halloween 3-6 at times, by not talking about Michael trying to kill his other family members, like Jamie. But during the begining when it shows newspaper clipings from Loomis's room one of them mentions Jamie Lloyd. If you look at the bus they ride on to Yosimite you can see the buses logos that are airbrushed out, very poorly!