Broken Base: Ignoring the continuity of the last three films. Some find it disrespectful to the franchise, while others are happy that the inferior films aren't considered canon. A third camp feels that this doesn't contradict anything that happened in the last three - as Laurie is mentioned to have faked her death - so the Jamie Lloyd films can still be considered canon even if the film doesn't acknowledge them.
Fanon: Some fans theorise that Jimmy from Halloween II might be John's father. Mainly because his death isn't confirmednote He's last seen passing out from a concussion in the car and he's outright confirmed to be alive in the TV Re-Cut. What's more is that Jamie in the previous three films has the same last name as him. This has led to some Wild Mass Guessing that Jimmy and Laurie got together, eventually faked their deaths out of paranoia and eventually split up.
Fanon Discontinuity: Most fans generally like to pretend the franchise ends with this film, despite the Word of God that this Michael Myers was intended as a copycat killer - and Resurrection retconning the ending.
Harsher in Hindsight: Michelle Williams survives a serial killer trying to murder his own sister and nephew. Fast forward to Shutter Island where she herself is the victim of a serial killer. But it turns out she herself was the killer - and drowned her three children.
Jamie Lee Curtis is the principal of a boarding school where serial killings happen. She moves on up to dean of a college and things get even worse.
Narm: The infamous "ice skate to the face" kill when you stop and think about it.
Nightmare Fuel: What Michael does to Sarah. He repeatedly stabs her in the back, and then strings her up for the others to find. To wit, when the lights are turned on, you could see directly through her body.
Tear Jerker: There's a deleted scene where Laurie learns from one of her students about the death of Jamie Lloyd, the daughter she abandoned to go into hiding for the duration of parts 4 through 6. Laurie excuses herself from the class, goes into a bathroom and promptly vomits.
Unintentionally Unsympathetic: Laurie if you consider parts 4 through 6 to be canon with this film, because that would mean she willingly chose to abandon her daughter by faking her death so she could go into hiding without thinking of what would happen if Michael ever tried to come after Jamie as well, which means everything that happened to Jamie Lloyd is just as much on Laurie's head as it is Michael's.