Continuity mistake: When Dum-Dum cuts the rope releasing Chug-a-Boom from the balloon, we cut to the car and you can see Clyde and Dum-Dum are surrounded by the rest of the Ant Hill Mob, but when we see the two in the next shot, the other members are nowhere to be seen.
Deliberate mistake: Season 2, episode 6 "Identity Crisis": When Bizarro starts decaying into the parody form of Superman, his costume goes with it; the blue fades, and even the 'S' insignia changes. Strange that superhero garments change right alongside their wearers when they suffer from an unstable genetic effect. Were the clothes cloned right onto his body, instead of sewn?
Visible crew/equipment: In the the episode "In-console-able" from series 19, in the kitchen when Paul accidentally puts custard and hundreds of thousands on a dinner, he puts the lid on it and when the camera zooms in you can see a cameraman with a camera recording and Barry getting ready for his take.
Emergency Marineville - S1-E11
Continuity mistake: When the second group of Spearhead jets take off from Marineville there are only two jets, but in the next shot you can see three jets, and in the next shot there are two again.
Duel Identity, Part II - S1-E30
Character mistake: Yugi mistakenly says if he doesn't get a monster out to defend himself Mai can attack him directly, which wouldn't be possible since the rules of Duel Monsters during the Duelist Kingdom arc forbade direct attacks on defenseless opponents. That rule wouldn't be implemented until the Battle City arc.
Audio problem: Billie says her line "he needs a new image" without moving her lips.
Fruit Picking Day/Daniel Is Big Enough to Help Dad - S1-E11
Revealing mistake: When Daniel picks up the can of blue paint, it passes right through the cans of yellow and red without bumping them.
Triumvirate of Terror! - S3-E8
Continuity mistake: When the camera first shows Jimmy, he says "Where the heck have you been" and looks up to his left then straight forward. The shot changes to a close up and suddenly he is looking up to his right. (00:00:15)
Continuity mistake: Before Charlie says to Lola "You must double-triple promise you'll never play with it", he places the rocket beside a black box. Later in the episode, when Lola attempts to get the rocket down to play with it, the rocket is now on top of the black box.
The Addams Family Goes to School - S1-E1
Continuity mistake: After Mr. Hilliard goes through gate and nears the house, it's really at the real house. A second later, he's approaching the now-familiar front porch on the studio set. This is easy to tell because the layout of the two porches are radically different.
Wind Chimes - S1-E9
Visible crew/equipment: In the scene where Mcduff and Johnson are trying to find water since it's extremely hot, they go Under The Bed and notice Alfred under there. Look in the background, for just a split second, you can a man walk past the from the door. It's for only a split second so it's quite easy to miss. (00:06:05)
A Case of Overexposure - S5-E8
Continuity mistake: In season one episode 16, Arnold says that him and Willis never met their landlord. In this episode they remember him as Mr Darcy - when they see him they recognise who he is.
Flipper and the Bounty - S2-E13
Visible crew/equipment: After Bud wakes up all alone in Bligh's cabin, he soon realises all the doors are locked. Then, just as Bud rushes over to the stern window (particularly the second time), a seated crew member is visible at the bottom right corner of the screen; we can see the movement of a leg and two hands (so, it's not a mannequin).
Continuity mistake: When Steve sings the Blue's Clues theme, he is wearing tan shoes he wore in few other episodes. When he drops his notebook after the theme, he is back in his brown shoes.
Continuity mistake: When Maya sits alone in detention, the door in the corner of the classroom randomly closes itself.
Factual error: Ralph asks Alice, "Remember me promising you I was gonna get you two tickets and take you to see a real Broadway show?" Alice replies, "Yeah, I remember. That was Thursday, August the 5th, 1942." That date was on a Wednesday.
The Fall Guy - S1-E4
Character mistake: Thorny tells Ozzie that Clara Randolph is throwing a party. When Ozzie tells David and Ricky about that party, he calls her "Mary Randolph."
Continuity mistake: When Janet gets off the phone with Clarissa's principal, Clarissa is standing on the right side of her friend. The shot changes and she is now on the left.
El traje del tío Jacinto - S2-E16
Visible crew/equipment: In the credits, there's a unknown person hiding behind Don Ramón (Raymond).
A Single Piece Was Lost - S1-E10
Visible crew/equipment: When the Gruenaks attack the Scientist a puppeteer is visible to the right of one of the Gruenaks, just before it grabs the bird cage and throws it onto the Scientist's head. (00:28:18)