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.
Continuity mistake: At the beginning of this episode, Cory asks Alan for money for his class photo. When Alan asks what grade Cory is in now, Cory says 11th. However, at the end of the previous season, Cory had just finished 9th grade (he and Shawn are both 15) and he spent his summer traveling the country with Eric. He should be in 10th grade, not 11th. This is further complicated later in the season, when he turns 16 and gets his driver's license. If he was in 11th grade, he would have already turned 16 and gone through driver's ed.
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 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.