Continuity mistake: At the nursing home near the end when Lois reveals that she knows 'Pablo' is really baby Stewie, Stewie's hat is on the table in between her and grown-up Stew. Shots pass and it changes to being in between the two Stewies. The scene cuts to Peter being silly and then cuts back to the home, where the hat has totally vanished and doesn't reappear.
Continuity mistake: When drunken Stewie is talking at the breakfast table to Brian, Brian has bacon and only one egg on his plate. After Stewie leaps from the shelf, Brian suddenly has two eggs.
Continuity mistake: When Stewie walks into the motel room and finds Quagmire tied to the bed naked, there is an establishing shot of Quagmire, and his hair is a crew cut, exactly like the one in "Death Lives". However, several scenes later when he is trying to use the phone his hair is back to the way it normally is.
Continuity mistake: During the water race at the start of the movie, Brad's mum's swimmers change from a one-piece at the start, to a two-piece at the end.