Continuity mistake: The age gap between Eric and Cory decreases as the series progresses. At the start of the show, Cory is in 6th grade and Eric is a high school sophomore, meaning they are four years apart, give or take a few months. By season 3, Cory is in 9th grade (confirmed by dialogue mentioning that Shawn, who is in the same grade as Cory, is 15 years old), and Eric is a senior, leading to an age gap of three years. The first episode of season 4 takes place a couple months after the end of season 3, with Eric and Cory returning from a summer Road Trip, but just two episodes later, Cory mentions that he is in 11th grade, while Eric is still barely out of high school, leading to an age gap of two years.
Continuity mistake: When the house is shown from the front exterior, there is a window on the left, but when seen from the interior there is a hat rack there.
Continuity mistake: Establishing shots of the Matthews' house show the doorknob on the exterior of their front door to be on the left-hand side, but shots from inside the house show it to be on the right-hand side.
Cory's Alternative Friends - S1-E4
Continuity mistake: Shawn claims his "sister, Stacey" uses the straightening stuff all the time. This is the only mention of her ever during the entire run of the show; and when Jack joins the show he is established as Shawn's only sibling.
Continuity mistake: When Mr. Feeny says "As if you are returning for your 20th high school reunion", there is a red crown on Mr. Feeny's desk with Minkus sitting on a chair at the end. After the camera cuts to a close up of Minkus saying 'More like a pre-union", there is a cut to Mr Feeny who turns to him. Minkus is all of a sudden holding the crown on his lap, then he is seen putting the crown back onto the desk. (00:04:00)
Continuity mistake: When Cory is getting food for Shawn, he's piling meat loaf onto his plate. There are three pieces, one on top of the other two, then they cut to a wide shot and back to a close up of Cory, and it's just one larger piece.
Continuity mistake: When Alan is talking to Cory in his room, telling him that he can always come home, he is pointing his finger at him. He has his right arm rested on his legs and is pointing with the left arm. Just before the shot changes to face Cory, Alan stops pointing. In the next shot, facing Cory, Alan has his left arm resting, and is pointing with his right arm.
Continuity mistake: Cory and Harley are out in the hallway after the bell rings, and Cory says he should be in history class, then when they are in Mr. Feeny's office, the bell rings again and Cory says his next class is American history.
Pairing Off - S2-E2
Continuity mistake: At the end of this episode when Eric & Cory are talking about Cory's date, Eric walks from his desk to the bed and we see the bedroom door is open, but when he walks to his desk from the bed the door is then suddenly closed.
Continuity mistake: At the end of the episode, when Alan is about to eat the cookie and Amy shows him what she is wearing, he drops the cookie onto his stomach. Later when Amy whispers something in his ear, Alan gets up but the cookie is gone.
Continuity mistake: When Eric is talking to his tutor in the hallway after recieving an A- on a test, there is a poster in the background for Sex Ed. This changes though, from saying "Sex, Ed?" to "Sex Ed" throughout the scene.
Continuity mistake: At the end of this episode, you see Griff standing with Joey and Frankie. He's wearing a jacket over a pink button down shirt that has a red collar and red accents. He sees a girl, and the camera moves to Joey who stands up on the bench and screams at the girl, then when the camera goes back to Grif, he's wearing a jacket over a plain old faded red shirt. I wonder what happened to the other shirt.
Continuity mistake: Shawn steals some fruit just before the interview starts. He empties the whole bowl into his backpack. When the interview starts, the bowl is full again, with the exact same fruits that were just taken by Shawn.
Continuity mistake: When Shawn is loading up his backpack with food from the catering table, a production assistant emerges from the kitchen and asks him if he's part of the interview. After Shawn says he is, the assistant walks away towards the front door. When the shot changes to the couch where the family is being interviewed, the assistant is nowhere to be seen, even though he walked right into the area of the shot. When the shot changes yet again, the assistant is back by the catering table, standing with his arms folded.
Continuity mistake: In this episode, Turner goes into a room and says it's his bedroom. But in "My Best Friend's Girl" Cory goes into that room and they say it's a closet.
Continuity mistake: In this episode Cory has a full length locker, but in the previous episode (Hometown Hero) He has the top locker. It's always in the same stop, so there is no way that he changed lockers.
Truth and Consequences - S3-E7
Continuity mistake: When they catch Janitor Bud on tape, there is a time clock on the wall. Through the rest of the episode there isn't.
The Last Temptation of Cory - S3-E9
Continuity mistake: When Shawn walks out of the front door of the Matthews' house, you can see some diamond fencing with vines on it on top of a brick foundation. But establishing shots of the house show no such feature by the front door.
Continuity mistake: When Cory is asking Mr. Feeny to call his parents to pick up him and Shawn, Feeny can be seen removing the white drape from the sofa. When the shot changes, Feeny has instantly removed the drape from the chair across from the sofa as well.
Answer: Topanga's middle name is never specified. Considering her sister's name is Nebula Stop-the-war Lawrence, Topanga's is probably something equally unusual.