Deliberate "mistake": When Tiffany calls Ruth Bailey, you can see that the mobile phone she uses is turned off.
Great sites
Mistakes
After seeing Frankenstein, Wolfman and a melted figure, Glenn walks by two set of shelves. On the second one, as he walks by, you see the gnome's reflection then the camera's reflection in a drawer. See more...
Seed of Chucky mistakes
Visible crew/equipment: When Redman arrives at Jennifer Tilly's house, in the front of his car you can see a camera operator.
Continuity: Towards the end when Glen cut his father's arm off, you see him lying there screaming and bleeding. The blood from his arm on the floor is making a puddle and then it cuts to Glen's face. When it shows Chucky's arm (or stump) again, there is no puddle, just blood following the crack in the floor tile.