Spoilers in my review:
I came into this movie expecting more than what I was given. So many movie critics and social media influencers were saying this was the next big hit and masterclass of horror for the 2020s. It fell flat and made me decide to only listen to horror movie critics who have experience in watching bad or mid ones.
The cinematography was beautiful, and the acting was good, with the expectation being Cage. His character didn't scream scary. It just screamed a character of what the 1980s extreme religious nuts thought Satanism was.
In the beginning, the movie was going places with some interesting concepts, but the storyline fell flat, and the characters started to act not like real people. Several major plot holes don't explain how things are the way they are. What caused Cage's character to be like that? How did those metal brains connect you to the devil? Was Longlegs using witchcraft, and why was he killing people? What was in the mother's closet? How did they figure out the killer had an accomplice if neither of them laid hands on the victims?
You can't turn off the belief for this movie since to have a believable movie, there need to be details based on reality; like how does an FBI newbie crack a serial killer code? Why didn't everyone not guess that the Cop's family was next? Why didn't the main character try to shoot the doll at the end? Why did she run after the serial killer and keep those darn doors open?
Is anyone telling you that the reason why people hate this movie is the lack of jumpscares or it being a slow burn is full of it. The movie doesn't make sense, and it became boring. I wanted to like this film but I can't. It wasn't the worst horror movie that came out this year, but it was a mess. I've seen better horror movies that had the devil or demons being the main villains.
Just like others are saying, the ads for this movie were scarier, and don't waste your money. Hereditary, The Witch, Prince of Darkness, Drag Me to Hell, and almost any horror movie with the addition of good and devil in its tags in Google would be 10× better.