A Long Walk To Pittsburgh (2) - S4-E17
Character mistake: In this episode Cory says that Topanga gave him his first kiss at age 13, but their first kiss actually happened when they were 11, in the 6th grade. (Season 1 - Episode 7 Cory's Alternative Friends).
Continuity mistake: Chet says he's spent the last year searching for his wife, but, when he left, Shawn was ending 7th grade and now Shawn is supposed to be sixteen.
Singled Out - S4-E7
Continuity mistake: When Eric answers one question, almost the entire group of girls leaves. In the next scene the stage is filled again
Singled Out - S4-E7
Continuity mistake: The same girls keep leaving the stage every time Eric answers a question.
Suggested correction: This is too vague. There are literally dozens of women that leave the stage whenever Eric answers a question. Describe what these women look like and what they are wearing.
Character mistake: When Cory is telling Shawn that he has a lot of questions about The Centre, Shawn invites him to check it out sometime. A couple scenes later when Cory does just that, an incredulous and defensive Shawn asks him why he is there, as if he forgot he invited Cory to check the place out.

A Long Walk To Pittsburgh (2) - S4-E17
Continuity mistake: When Topanga comes back to see Cory, for the whole period of time that she is there, sometimes her hair is dry and straight, and others it's wet and wavy. (00:07:12 - 00:21:16)
Revealing mistake: While the girl who just broke up with her boyfriend is on the phone with the ex, she is throwing his stuff out the window. As she throws the last couple of CDs out the window, you can see the backdrop of the beach sway a little bit.

Visible crew/equipment: When Eric jumps out of his chair and exclaims "No" during his college acceptance interview, a boom mic can be seen being pulled out of view. (00:19:00)
Revealing mistake: You can tell the ocean visible from the dorm room window is just a backdrop, as there are no waves approaching the shoreline.

Continuity mistake: When Amy is trying to get Alan to back off Mr. Mack, the way her hand is gripping his arm changes between shots. (00:16:45)
A Long Walk To Pittsburgh (2) - S4-E17
Continuity mistake: After Cory finishes explaining to Amy why he loves Topanga, he sits down next to her and begins placing his arm around her. When the shot changes, his hand is instantly resting on her shoulder.

A Long Walk To Pittsburgh (1) - S4-E16
Continuity mistake: After Cory finishes downing his soda, he places the cup on the table. When the shot changes, his hand is instantly away from the cup. (00:16:37)
A Long Walk To Pittsburgh (1) - S4-E16
Character mistake: After learning that Topanga will be moving to Pittsburgh, Cory tries to rationalize their desire to be together for the rest of their lives despite still being so young by comparing their relationship to that of Romeo and Juliet, thinking they turned out OK. Shortly thereafter, he is shown reading the book in his backyard and explains the situation to Mr. Feeny, who advises him to skip to the end to find out what happens to their relationship, much to Cory's dismay. The problem is that Cory already learned the fate of Romeo and Juliet in Mr. Feeny's class in the first episode of the series. He was even dismissive over the idea of a man killing himself over a woman.

Continuity mistake: When Alan is saying "It's a miracle bra, honey, get a camera," his left hand is resting on the table. When the shot changes, his left hand is suddenly resting on his right arm. (00:08:00)
Continuity mistake: When Eric is suggesting to Mr. Feeny that they go out and look for women, some shots show Feeny gripping his wine glass, while other shots show his hands down on the table with the glass several inches away.

Continuity mistake: When Mr. Timmer picks up the mini vase, just before Cory tells him to put it down, you can see he is the only one touching it. When the shot changes, Mr. Timmer and his wife are both holding onto it. Cory also instantly has his left arm raised and index finger pointed at the Timmers.
Continuity mistake: When the bartender fills up the mug of root beer, after the foam settles, the mug is a little more than half full. When Mr. Feeny hands the mug to Eric, it is suddenly filled closer to the top.

Continuity mistake: When the bartender fills up the mug with root beer, the foam has instantly settled when the shot changes.
Continuity mistake: When Eric is performing his one-man show, he states in the intro that he was born on June 24, 1978. However, in the season 1 episode "It's a Wonderful Night," Eric fails his test to get his driver's license. That episode takes place during the middle of the school year, but if Eric was born in late June, he would have had to wait until after, or at the least the very end of the school year to try and get his license, as the minimum age in Pennsylvania for obtaining a driver's license is sixteen.