During the tour of the Duff Brewery, the three vats are marked "Duff", "Duff Light" and "Duff Dry". The vats are filled by the same pipe, indicating different names for exactly the same product. This may be reference to an urban legend that some gas stations hooked up their regular, plus, and super unleaded to the same tank, charging more money for customers who bought plus or super while getting the same product.
Related to this gag, this same scene has been used to show the aspect ratio differences between the original 4:3 as seen on Fox and on the DVD releases and the the 16:9 versions seen on FXX and Disney+. In the 16:9 version, the pipe is cropped out of view making it seem like they are indeed three different products.
Martin had a flying balloon which was deflated when Nelson shot it from his B.B. Gun exhibit. Nelson states that he was aiming for Martin's head. In the syndicated version, both Martin and Nelson's exhibits at the Science Fair were removed. In the DVD release, this scene was left in uncut.
Also cut in syndication is the scene of Chief Wiggum accidentally showing a home video of him eating a hot dog in a kiddie pool (and later spraying his wife with a hose) during the anti-drunk driving class.
This is the first appearance of Sarah Wiggum (Chief Wiggum's wife).
It is revealed Hans Moleman is 31 years old and looks old because of severe alcoholism (though later episodes would have him as 80 years old).
This is also the second episode to imply that he was significantly younger than his appearance would suggest, as he was mentioned to have been born on August 2, 1961 on his driver's license in the episode "Selma's Choice" (which at the time of airing was on January 21, 1993, which would make him roughly that age).
When Barney is talking to the quality control worker, one of the bottles that pass by is actually a jar with Adolf Hitler's head in it.
The closeup of Homer saying "D'oh" when he gets arrested for drunk driving (even though he wasn't) is from Bart the Daredevil when Homer says "D'oh" after Bart makes an insincere promise not to jump the Springfield Gorge by himself to Homer.
On Homer's fake ID, his name is listed as Brian McGee. His date of birth is also listed as August 2, 1948.
Bart hurling Lisa's science experiment at Skinner's posterior while the latter was tying his shoes was similar to the Picture Day level in Virtual Bart, where the player can throw (regular-sized) tomatoes and eggs at Skinner's posterior while he is bent over and not get in trouble. Coincidentally, both this episode and Virtual Bart were released within the same year.
Lisa asks Bart to hold the giant tomato and Bart answers "Certainly" and laughs, in reference to a catch phrase of Curly Howard from the Three Stooges.
Martin is dressed up as Phileas Fogg, the main character from the Jules Verne novel Around the World in Eighty Days for his science fair project.
The final scene in which Homer and Marge ride off into the sunset singing B.J. Thomas' "Raindrops Keep Falling On My Head" parodies a similar scene in Butch Cassidy and the Sundance Kid.
In the scene where Homer returns to Moe's Tavern, you are able to see two Larrys at once; sitting drinking beer amongst other patrons.
It's quite impossible for Homer to be listening to Queen when he was 17. Since Homer is 37, and the episode was released in 1993, that means that he claims he was listening to Queen in 1973. He has a poster hung on the wall of the album A Night at the Opera,l which was released on November 21, 1975, when Homer was 19.
The fake ID card Homer shows has an age on it which wouldn't make sense, as the card's shown age would have to change yearly.