Question: At the beginning of the movie, the entire Good Guy factory is completely covered in dust and cobwebs because of not being used in eight years. What caused the factory to close for such a long time? Nobody believed Andy when he said that his Good Guy doll was possessed by Chucky. And even though Andy said Chucky was responsible for so many murders in his doll form, people most likely wrote it off as a child's overactive imagination and that wouldn't be enough to close down the factory.
Question: Has there ever been any explanation as to why Freddy was killing children?
Answer: In the book version of the first three movies, he took a saying from his abusive foster father: "Children are useless." He made it "Children are better off dead." He also killed one trying to rob him and felt a rush of adrenaline from it that he didn't want to lose, so he got addicted to killing.
Question: So how exactly did Max Cady slip past Kersec's security system and get into the house? Did he kill the maid outside and then just walk in disguised as her?
Answer: He snuck in during the day and hid, before Kersec's teddy bear security system was set up. Sam Bowden realises this when he wakes from a nightmare. Its how he was able to poison the dog which hadnt been let outside. Max Cady killed the maid in the pantry with the same piano wire he later attacks Kersec with.
Answer: Kersec suspected that Cady might attempt to break into the Bowden house if he thought it was empty. His plan was for Cady to break in and then be shot dead as an intruder. He likely lessened the security to allow Cady to break in. Cady killed and then impersonated the housekeeper to get in.
I like your answer but I'm a little confused by the "lessened the security" part. If I'm not mistaken, every possible point of entry into the house at least from the ground floor was connected to the bear via the fishing line, so Kersec would know if a point of entry was disturbed by the bear moving. Where would Kersec lessen the security from that standpoint, especially since his setup was supposed to be foolproof?
Kersec wanted Cady to be able to break in so that there would be a plausible reason to shoot him dead. The idea is to make it look like his death was a result of self defense. I'm only speculating that Kersec made it easier for Cady to break in into the house. Being as it was his security system, he would know how to make it possible for Cady to get in.
Answer: The public believes that the Good Guy doll that committed the murders had simply malfunctioned, which caused great negative publicity for the company. The public does not believe Andy or his mother's claims that the doll was possessed by a serial killer and was actually alive. In Child's Play 2 the company finds and reassembles the doll to prove to shareholders that the Good Guy doll is safe. This backfires and the doll is re-possessed, which leads to additional murders in that film crippling the company for 8 years.
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