Continuity: When coming down the dome the height of Homer on the dome changes between shots.

Deliberate "mistake": When Homer is on the wrecking ball, he hits a fork on one side but in the next shot it vanishes.

Continuity: After Grandpa goes nuts in the church, they go to the car. You can see that Homer has a seat belt on, but when Marge gets out he does not.

Continuity: Willies hair changes from red to brown throughout the film.

Continuity: When the Simpsons see the nooses in their backyard, you see two kids put a pacifier on Maggie's noose, but in the next shot where you can see the nooses, the pacifier is gone.

Continuity: When the wall is put up around the lake it is built right next to it, but when Homer dumps the silo the wall's much further away from the water.

Continuity: During the bike stunt at the end, Homer's hair flows in some shots, but is completely rigid in others.