Kristina Klebe knew both Robert Curtis Brown (her father in H2) as well as Nick Mennell (her boyfriend in the first Halloween) before shooting. Rob Zombie had no idea and all the casting was random. Though when he told her about casting her boyfriend in the first film he said he was looking at a few people but he needed someone who could match her height.
Laurie has a picture of Charles Manson over her bed. Later, after Lynda's father tries to kill Loomis, it is revealed that the gun was not loaded - just like the gun Manson follower Squeaky Fromme pointed at President Gerald Ford.
In the director's cut, Micheal takes off his mask and yells "Die" before stabbing Dr. Loomis. Based on this scene, it marks the first time ever in the series where Michael Myers actually speaks. This is also the first time the characters face can be seen clearly.
The trivia items below may give away important plot points.
Director's Cut Body count = 20 (plus the two people on screen and the one person off in the opening dream sequence); Theatrical cut = 19. In both cuts, two people are not killed by Michael Myers. There is also a pit of dead bodies that Laurie falls into in the opening sequence, but it is not verified that Michael killed them.
Despite this being Danielle Harris's fourth appearance in a Halloween movie, this is the first in which her character has died. However her previous character Jamie Lloyd was killed off after she was recast.