Chucky mispronounces the French words of the voodoo chant. Instead of saying "Pouvoir des morts" (power of the dead), he says "poivre de le morte" (pepper of the dead) with quite a few spelling mistakes.
When Detective Norris asks Santos if he's seen Chucky anywhere, he says "Who's Chucky?" and confusedly, "Why would I know anything about a doll?". Yet earlier at the station house, he was asking Andy "So why did Chucky want to see Eddie?" indicating Andy had told him pretty much everything.
When Chucky is strangling Norris in the car, Norris burns Chucky's face with the cigarette lighter, to which Chucky screams in pain and eventually lets go of the rope. However, after the crash, Norris shoots at Chucky and Chucky laughs saying that he cannot be hurt. Then later when he goes to see the voodoo priest, he references being shot as causing pain, but not the cigarette lighter.
When Andy makes his mother breakfast in bed, the drink initially looks like orange juice when he pours it in the kitchen and walks down the hall. But then in his mothers bedroom the drink looks like milk.
When Andy pours the cereal, and then the milk, there is cereal on the counter, to the left of the bowl. There is loads of cereal on the counter, then when Andy puts the burnt toast onto a plate, there is much less cereal. Then when he takes the tray from the counter, there's now loads of cereal on it.
When detective Norris is driving and Chucky is trying to stab him through the car seat, Norris clearly puts his feet up on the dash in the in-car view. But there are no feet on the dash on the outside view of the car. Also, when Norris does the 360 in the car, you can clearly see the driver is wearing a beanie, but Norris had nothing on his head.
When Chucky first speaks to Karen, she drops him and he rolls under the couch. The middle skirt is clearly pulled back to allow him to roll under, but in the next shot she gets down and has to lift the skirting of the couch up.
When Karen Barclay is looking at the Good Guy box where it says "Batteries Included", it says "Play Partners Toys" in the bottom left-hand corner. The company that produces the Good Guy dolls is called "Play Pals Toys", not Play Partners.
When Chucky's body is attacking his partner he uses the same gun Katherine had in the living to shoot it in the heart. However Katherine is shown pulling the trigger of said until no rounds are left in the cylinder and was therefore empty when she came back to the bedroom with it.
When Dr. Ardmore tries to give Andy the injection, Andy struggles from his grip and then grabs his glasses from his face. Then in the next shot of him, his glasses are back on his face. In the following shot they've gone again.
Towards the end of the movie while Andy's mother is looking for the man who sold the doll to her, she finds him and asks him if he remembered her. She says she had bought the doll the day before when in actuality she bought it days ago.
When Chucky first leaves the lift near Andy's apartment he seems to be heading for the door but a few scenes later he is seen coming down the chimney but there is no way Chucky could have done that inside the building. He would had to go back outside and climb the building to get to the roof.
Near the end of the movie, Chuckie stabs the cop, Mike Norris, in the leg, and he falls and remains in the bedroom. Shortly after this, Chuckie is shot several times by Karen, and his body parts are severed. This occurs in the living room and hallway. Mike Norris, still on the floor in the bedroom tells the backup cop who then arrives that Chuckie was shot and that his body is in pieces all over the place and to not touch any of them. It is impossible for Norris to know or to have seen any of this, as he was in the other room the entire time.
Somehow Andy was able to skip school and travels on a train free of charge. A lot of adults should have assumed Andy was supposed to be in school and there should had been a conductor on the train to charge Andy fares.
The events of the film obviously take place in the middle of winter. When Andy goes to wake his mother up on the morning of his birthday, the living room is filled with sunlight, and he pulls the curtains in the bedroom open to let a great deal of light into the room. However, Andy's mother tells him "It's only 6:30 in the morning." Depending on the month, the sun would either just be rising or not yet have risen at 6:30am in Chicago, not shining as brightly as it appears to be.
When Mike is in the car being attacked by Chucky, after he hits a metal can and makes sparks, he swerves violently in the road, and on the road you can see several pairs of dark skid marks in the exact same place as he swerves, obviously from previous takes.
When Karen & Andy set fire to Chucky, he emerges from the fireplace still on fire and in a frenzy. He clearly sets fire to at least two pieces of furniture in the room, yet no one even tries to extinguish them. Nor does the fire appear to worsen.
When Chucky is attacking Mike in his car, Mike rises off the seat to try to avoid the knife stabbing at him from the backseat. At one point Mike raises both his legs way up on the dash, yet the car's speed never slows.
When Maggie's body landed on the pickup, the hand is visibly a mannequin's hand. Also, Maggie managed to flip to face up position by the fourth floor. It is unlikely for Maggie to flip back to face down position and land on the van as shown.