My thoughts on the movie (Spoilers)
It was simply eh. I was very disappointed and thought they could do better, even though Scott who created fnaf worked on it but I still was disappointed.
I loved the fact that they showed the animatronics with an eerie atmosphere, the killing part was nice for a PG-13 movie. The children in his dream set up an eerie sense as well. While I hoped there to be jumpscares, I didn't get a single one and was just at shock at the end of the movie from disappointment. I liked the nostalgia of the game, but wish it could've been more scarier to make me get a jumpscare.
Now for the lore, the baddest part of them all. They simply went off the whole fnaf lore, the lore in this movie was just everywhere and dumb. Things were so confusing and I didn't like how everything turned out at the end. Michael Afton isn't an afton, but a random person who William wants to kill. I mean all his victims are random children but Michael is just some guy. So this just drives off the whole lore. Michael is supposed to be dead after his guts were scooped out from Sisters Location, Elizabeth his only daughter who was replaced by Venessa in Secruity Breach who is later a serial killer. Elizabeth died as a child as she was consumed whole by Circus Baby in her stomach, and his younger son aka the Crying Child being a victim of Bite '83. And William dying inside Spring Bonnie while trying to hide from the animatronics, with the moist atmosphere making the spring traps kill him and withering inside the suit becoming Spring Trap. Not him dying in already withered Bonnie suit.
Everyone died, and his wife is well... Idk abt her. But his best friend/co-founder Henry wasn't brought up or his daughter being a victim which is fine. But the whole lore was just everywhere that it came to a point where I didn't like it, if they focused on how some random security guard not Michael but some rando and made him work there would've been a nice set up to the lore exploration giving us a backstory of William and the children who died and are still inside the animatronics. But in this movie they made the children forget who killed them, which was William which is confusing. And they plan to make a sequel which could've been like a lore explanation if they went the right path.
Overall, a good attempt and good movie if you don't care about the lore nor the jumpscares. If so, you're just getting a slightly water down version of M3GAN. [These are just my opinions btw.]