Unlike most films, the introduction portion of Halloween is rather brief. It only lasts about eleven minutes. This act begins on Halloween night in Haddonfield, Illinois, in 1963. We witness, through a POV shot, young Michael Myers murder his older sister and get caught by his parents. After that, the movie jumps ahead 15 years, to 1978, where we are introduced to one of our protagonists, Dr. Sam Loomis. He is Michael's psychiatrist and is traveling to the sanitarium where Michael is being held, so he can transport him to a court hearing. During this scene is where the first act peaks. Michael manages to steal the car that Loomis was in and escape. The question that is asked by the end of this act is: where is Michael going to go? Thus ends the first act.
The complication section of the film returns to Haddonfield, where Michael has escaped to. Here, we are introduced to our other protagonist, Laurie Strode. This section of the film introduces us to her and her two friends, Annie and Linda, and informs us a little about them. Also, in this section, Dr. Loomis arrives in Haddonfield in pursuit of Michael, absolutely sure that he has returned there. The first half of this act mainly features Laurie and her two friends being stalked by Michael. The second half, however, raises the stakes. While Annie and Laurie are babysitting two neighborhood children and Linda is on a date with her boyfriend, Michael continues to stalk them for a little bit until he finally goes after them, one by one, to kill them. The deaths of Annie (at 53 minutes), Linda's boyfriend (at one hour and five minutes), and Linda (at one hour and seven minutes) are, undeniably, the high points of this act. Also, this act covers Dr. Loomis' and the Haddonfield Sheriff's search for Michael. This takes place mainly at Michael's old, abandoned house, where Loomis waits for Michael to show up. The complication section lasts for about fifty-eight minutes. The question posed by the end of this act is: what is going to happen to Laurie?
The resolution portion of Halloween begins with a quick cut to Dr. Loomis, still at the Myers' old house when he notices the car that Michael stole. Then the film cuts back to Laurie who, having just gotten off the phone with who she thought was either Annie or Linda (whom it was, being strangled to death) and having seen the lights at the Wallace house across the street where she believed the call came from (the same house where Annie, Linda, and her boyfriend were murdered), decides to walk over there and see if everything is alright. When she arrives, she goes upstairs and finds the bodies of the three victims and encounters Michael, who tries to kill her. The rest of the act features Laurie trying to escape from Michael. This leads to the high points of the act, which are when Laurie is trying to escape from the Wallace house, Laurie trying to get into the Doyle house (where she was before), Laurie hiding from Michael in a closet, and Michael standing back up while Laurie, thinking that he is dead, is not watching. Also, the two kids who were being babysat manage to attract Dr. Loomis' attention, who shows up just in time to shoot Michael as he is about to kill Laurie after sneaking up on her. This leads to the final peak of the act, in which Loomis goes to find Michael's body and discovers that it is gone. This scene concludes the film. This act lasts about twenty minutes. So, in defining acts, this act can be called a resolution, although that can be argued against, due to the fact that some things are left unresolved so that title can be misleading.