The knife Charles Lee Ray uses during the flashback sequence is the same knife Chucky uses throughout the first Child's Play movie.
According to Brad Dourif, he had to wear a wig and massive amounts of make up to make him look like he did in the original Chucky - Die Mörderpuppe (1988) movie. Lighting was also a huge factor.
The actress who plays Nica, Fiona Dourif is the real life daughter of Brad Dourif, who provides the voice of Chucky.
The makers had a practical joke at a bus stop to promote the film. A billboard of the movie's poster would light up and an actor dressed as Chucky would suddenly bust through the billboard and scare whoever was nearby.