Continuity mistake: Bartman Begins: When Chief Wiggum arrives to arrest Skinner, Lou and Eddie are behind him. Eddie on Wiggum's left and Lou is on Wiggum's right. But a couple of seconds later, when the three walk over to Skinner, Eddie and Lou have swapped places.
Continuity mistake: Mob Rules: Just after Quimby announces the Grand Theft Scratchy ban, Groundskeeper Willie and Lenny swap places between shots.
Continuity mistake: Big Super Happy Fun Game: When Homer tells Milhouse to beat it, he raises his right fist and leaves his left arm at his side, but when the shot cuts, his left fist is also raised.
Continuity mistake: Lisa the Tree Hugger: When the cutscene opens on Bart and Lisa standing outside the logging company, the establishing shot shows them with their backs to the main door. When the shot cuts, they have rotated 90° so that the main door is positioned to their left.
Continuity mistake: Enter the Cheatrix: Whilst Bart and Lisa are talking Professor Frink after arriving in the Game Engine, there is a large green pipe that is positioned behind Bart and Lisa during the conversation. Later in the cutscene, when Frink is grabbed and taken away by the giant ape, the green pipe is now a few meters ahead of them.
Continuity mistake: Enter the Cheatrix: When Professor Frink climbs down the ladder to talk with Bart and Lisa after he is saved by them, they stand next to a large machine that Frink uses to bring a Rift Portal to them. At the start of the cutscene, the arrow on the right-hand side of the machine is pointed to the left. When the Rift Portal appears, the arrow is pointed to the middle.
Continuity mistake: Enter the Cheatrix: When the Rift Portal appears after Frink gives Bart and Lisa the strategy guide, in the shot of them getting inside the portal, a piece of paper with some test results can be seen sticking out of the side of the portal. In the next shot, the results shown on the paper have suddenly vanished, leaving the paper blank.
Continuity mistake: Enter the Cheatrix: When Lisa knocks on Professor Frink's door, the box of band candy that Bart is holding has no text on the right side of it. Bart then raises the box saying "I gotta move this candy" and the words BAND CANDY have suddenly appeared on the side of it.
Continuity mistake: Medal of Homer: When Bart asks what war they are in, Homer replies saying it's the Civil War, and he raises his right hand. When the shot cuts, his right hand is lowered.
Continuity mistake: Five Characters In Search Of An Author: When Matt Groening is watching Homer and Bart through the security camera footage, his hands are clasped. When the shot cuts, his hands are apart.
Continuity mistake: Enter the Cheatrix: When Bart and Lisa approach Professor Frink's front door, in the wide shot, Bart and Lisa step on the front step and Bart is shown standing on the left hand side of the step and Lisa is standing on the right hand side. When the shot cuts to a closer angle of the two, Lisa is standing more to the middle.
Other mistake: Game Over: When Lisa has finished building the stairway to heaven, there is a shot shown from behind the large crowd of people that pulls back to reveal the stairway of Springfield buildings. In the shot, everyone in the large crowd appears to be looking at the stairway, but Private Burns appears to be looking off to the right and not at the large stairway.
Continuity mistake: Game Over: When Lisa has finished building the stairway to heaven, there is a wide shot that shows the stairway complete in its entirety. When the shot cuts to Lisa, she has suddenly appeared at the bottom of the staircase.
Continuity mistake: Game Over: In Bargain Bin, when the mothership fires on the Simpson house, it destroys the mailbox. When they return in Game Over, in the establishing shot of the house, the mailbox is suddenly back and intact.
Continuity mistake: Game Over: When everyone begins running through the door back to Springfield, a few extra pieces of rubble suddenly appear next to the door when the shot cuts.
Revealing mistake: Mob Rules: When Marge and Lisa witness Martin carjacking Ned, in the shot of Martin saying "Gimme your ride, jerk", Marge raises her hand to her mouth. When she raises her hand, part of the baby carrier she is carrying Maggie around in is not fully drawn in.
Other mistake: Mob Rules: In the opening cutscene for Bartman Begins, Uter, Ralph, Jimbo, Dolph and Kearney are seen queueing outside the Sequel Stop store. In the opening cutscene for Mob Rules, the exact same group of people can be seen coincidentally queueing outside the same store, despite the passage of time.
Revealing mistake: Bargain Bin: When the Simpsons are sitting at the computer, the Ethernet cable seen coming out of the back of the computer doesn't appear to lead anywhere. The Ethernet cable is shown attached to the computer, but it ends after a few inches and is not attached to anything else. The animation for the cable was incomplete.
Continuity mistake: Big Super Happy Fun Game: When Homer is handed the Sparklemon after he and Lisa defeat Ralph, his left arm is raised when he grabs onto it. In the next shot, his left arm is at his side and the Sparklemon has disappeared. The same mistake is also made when they defeat Sherri and Terri.
Continuity mistake: Grand Theft Scratchy: Note the background behind Marge, Lisa and Poochie at the start of the ending cut scene. You'll see there are no cracks on the floor between the barriers and the concrete wall a few meters behind them. In the next shot, as Marge says "Sorry, Poochie" to Poochie, a crack on the ground has suddenly appeared between the barrier and the concrete wall.
