Trivia: The trivia and in jokes abound in this film. Firstly, you have Janet Leigh (Jamie Lee Curtis' mother) playing Norma (reference to Psycho) and complaining that the "showers are blocked again" (second reference to Psycho). In her last scene in the film, Janet Leigh is about to get into and drive away in the same car that she used in Psycho.
Trivia: Late in the film, before Laurie/Keri goes back inside to battle Michael alone, she tells John and Molly to "drive down the street to the Becker's". This is a reference to "Scream," in which Casey Becker's father told her mother to go "down the street to the Makenzie's", a line included in the original Halloween.
Trivia: Not a mistake, just something to notice: When the guidance counselor is checking on Molly and Sarah, they are watching Scream 2, the scene where Cici (Sarah Michelle Gellar) gets killed. As he enters the room and says their names, watch the TV. As he says "Sarah", Sarah Michelle Gellar turns around.
Trivia: One of the biggest hurdles of the film? Oddly enough, it was choosing the right design for the mask. Director Steve Miner originally wanted a more stylized, paper-white mask and several scenes were shot with this original design. However, the producers felt the mask didn't look right and wasn't menacing enough, and thus the design was changed into one based more around the look of the mask from the previous film ("The Curse of Michael Myers") and included more detail and shading. Director Miner protested, but his attempts to go with his first design were vetoed. Nevertheless, the original mask can occasionally be seen in the film for some scenes they didn't want to reshoot (mainly sequences with Michael in the distance), and in some of the trailers.
Trivia: Originally composer John Ottman wrote an entirely different score for the film - one that was more whimsical and less traditional. The producers panicked at the last minute, feeling much of the score didn't work for the film, and had to bring on fellow composer Marco Beltrami to write new music to fill in the gaps. Unfortunately, due to the limited time, Beltrami could only write minimal original music for the film, and thus cues from some of his other scores (notably "Scream" and "Mimic") were recycled and reused in the film.
Trivia: In the first movie, Laurie sees Myers while she is looking through a window during school. The teacher surprises her by asking her a question and her answer is about fate. When she looks back out the window Myers is gone. In H20 Molly is looking out a window during school, she sees Myers, Laurie asks her a question and her answer is about fate. When she looks back out the window Myers is gone.