People are afraid of the dark. Maybe not always the physical, non-light variety, but the empty cold nothing that comes with lack of knowledge. As sight-first beings, we conceptualize this by "the dark," going back to the first days when predators hunted at night and the only safety we found as creatures with no claws or teeth was up a tree or by the warmth of a campfire. This instinct to fear the unknown fuels the legacy sequel that is the new horror film from Blumhouse Halloween.
The original Halloween focused on this fear of the unknown. A masked crazed man, for no discernible reason, shows up in his hometown and begins killing people. Quaint by today's horror and real life mass killings, Michael Myers kills five people on Halloween night, 1978 or 1977 or whenever it took place. Like the shark from Jaws before him, Michael Myers in that film has no other reason for his actions given other than carnage and death. Not until the sequels did we get the sister backstory and the cult and all the other nonsense. People attempted to give reason for the madman to do what he did and diluted the product. Because Michael Myers is most like the shark, in that his only purpose is to move and kill (he doesn't even make little baby Michael Meyers), he embodies the unknown and the darkness.
As I said, later sequels drew on backstory to fill the horror. In the direct sequel, the final girl Laurie turns out to be Michael's sister. Following sequels filled in his desire to go home, his deification by a cult, and his further attempts to kill his entire family line. Other horror franchise also went this route. Jason of Friday the 13th avenged his mother's and his own death by killing counselors and other teenagers who sinned (sex, drugs, general party behavior) or who just got on his land. Jason is the ultimate zombie redneck killer. Freddy of the A Nightmare on Elm Street sequels is all personality, telling jokes while killing the teenagers of the people who killed him in an attempt to gain more power, an extension of his own child-killer roots when he was human. Michael Myers, Jason, and Freddy are all linked as icons of 1980s horror by the excess of their sequels, but only Michael survived clean, his backstory not coded in with the first entry in the series. As the new film is a direct sequel to that first movie, unlike Jason and Freddy (accepting New Nightmare), writers can discard all but the bare-bones, shark-like nature of this mass murderer.
As a sequel, the film also succeeds by updating and following current trends. Discarding all the messy backstory of Michael and Laurie's relationship, it gives it a purity. He's a killer, and she's a survivor. Sure, it muddies the water with plenty of explanations and dismissals of motive. The sister plot is written off with a single joke. A doctor tries to give a Batman/Joker-like meaning that one cannot survive without the other. The truth in the film, though, is that it takes extraordinary circumstances to pit hero versus villain in Halloween (2018). The shark does not care and kills indiscriminately for most of his run time. The story may have even been served better taking a page from the Jaws script with our heroes chasing him down in the last act rather than what does happen. Sure, a booby-trapped Home Alone style house in the woods is interesting, but the peril does not seem all together there as Michael does not seem interested in killing these people, just people in general. The most effective parts of the movie are the waiting to see, the heroes catching up to the carnage at the beginning. While we may have some catharsis in seeing the wounded survivor Laurie and her family catching and killing the monster that destroyed their lives, the end result is an unsatisfying character development as so much time had to be devoted in getting them together.
Still, we are given no true motive for Michael's spree and are left with the idea that the shark may still be loose among us, a terrifying thought. Bringing back the idea that a creature with no remorse may find us, destroy us, harkens back to that old feeling of watching the fire die out late at night. That feeling that out there in the dark lies something that will invade our safe houses and kill us for no other reason than that's what it was made to do. The success of the original and this legacy sequel of Halloween is not that we are afraid to go into the water, it's that we are afraid to turn off the light.