Continuity mistake: When Bart is standing on the bench, Jimbo and Milhouse are standing in the front row, on the right side of the screen. But when there's the closeup (a second later), there are children shown in front of Jimbo and Milhouse and the girl with the purple hair is gone.
Continuity mistake: When the Stonecutters are singing "We do", the position of several characters, particularly the Martian and Chief Wiggum, change randomly as the camera angles change. The Martian starts at the end of the table on the right side, with Chief Wiggum two seats to the left of him. In later shots, the Martian, then Wiggum are both switched to the same position, midway up the left side. Then, when the song ends, Wiggum has disappeared, and the Martian remains in this new position.
Continuity mistake: In Hungry are the Damned, when The Simpsons are on the spaceship and the aliens show them the food, there are 3 pots and two plates. Yet when the shot changes there are 4 pots and no plates.
Continuity mistake: When the Simpsons are eating and the family are praising Marge, Homer's plate is first seen to have a small amount of yellow food and a bit of pink food (meat?).In a later shot when Homer steals and uses Marge's pepper spray he has a large pile of yellow food.