Toucan Sam, Trix, Cap'n Crunch and Count Chocula are all featured on Bart's "Cereal Killer" game; they are, respectively, the mascots for Fruit Loops, Trix, Cap'n Crunch and Count Chocula breakfast cereals.
Alberto's shirt changes from blue to tan when he's thanking Marge.
In Lisa's First Word (1992), we see that Homer met Ned Flanders when the Simpsons first moved into 742 Evergreen Terrace, yet in this episode, the Simpsons' and the Flanders' met while Homer and Marge were still dating.
In When Flanders Failed, Marge tells Homer that he can't hate Ned just because they have a better lifestyle. She seems to have forgot that he made them sleep in separate rooms.
Marge either forgot, or just didn't care about it, seeing as it was a long time ago.