Continuity: 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.

Revealing: When Eric first meets Mr. Feeny's niece, he throws a bag of mulch. When the mulch lands, you can see the fake grass move, and the fake background swings a little bit.

Continuity: When Allen is telling the rocket story to Cory, he metions the "Franklin Space Museum." The real place in Philadelphia is actually called "The Franklin Institute."