Continuity mistake: In one scene, Chucky and a girl are driving down a road when they get pulled over by a cop. The cop is surprised to see a "Good Guys" doll, and is shocked to see that its nose is bleeding. They do a close up of Chucky's nose, and blood is running from it. When they cut to the cops point of view, where Chucky and the girl are both in frame, the blood is gone. It doesn't reappear for the rest of that scene, even though no one wiped it away.
Continuity mistake: Chucky's eyes are made so that they blink and move. However, in the scene where the business man is stuffing Chucky into the trunk of his car, Chucky's face is different because his eyes are drawn onto his face. The same thing happens with his mouth throughout the movie.
Continuity mistake: When Andy is tied up on his bed, the two skipping ropes tied to his feet have green rope, but in one closeup of Andy kicking his foot about, the rope is yellow, then in the next wide shot, is green once again. (In the closeup of Andy kicking his feet he has also gained slippers!)
Continuity mistake: The small cupboard where Andy finds Chucky hiding in, in Miss Kettlewell's classroom is full of toys. When Miss Kettlewell grabs Chucky from the cupboard you can see there is a toy crocodile in it, but in the next wide shot of Andy at his desk, you can see the open cupboard, and the crocdile has vanished, along with other toys changing position.
Revealing mistake: In the full-screen version, a piece of Chucky's animatronic equipment can be seen bobbing up and down with him (the bottom-left corner) as he chases Miss Kettlewell in the classroom.