On the Simpsons' mailbox, you can see the Simpsons logo and the TCF copyright info.
The Music "Duel of the Fates" from Star Wars Episode I: The Phantom Menace plays while Bart and Skinner are fighting across Springfield. It plays again later in the hospital scene when they throw peanuts and shrimps at each other.
Skinner screaming "Nooooooooo!" after Bart tells him he was El Barto parodies the scene in The Empire Strikes Back where Luke screams "NOOOOOOOOO!" after learning Darth Vader was his father.
Polybius is one of the arcade games in Captain Blip's Zapateria at Springfield Mall. It is shown with only one button and printed with the words "Property of U.S. Government". Polybius is a reference to a Popular urban legend about an supposed arcade game released to the public in 1981, and caused its players to go insane, causing them to suffer from intense stress, horrific nightmares and even suicidal tendencies.
The game Triangle Wars has the logo shaped in a clear imitation of the shaping of the letters on the Star Wars logo, with the "s" on the end of wars looking exactly like the "s" in Star Wars. In addition, Triangle Wars is a game where the player flies a spaceship, yet another reference to Star Wars in this episode. This video game also parodies the arcade games Asteroids and Qix.
The book "Kansas City Royals: Forever Champions" is on sale at Rock Bottom Remainders - the Royals won the 1985 World Series but lost over 100 games in four out of five seasons from 2002 to 2006.
The book shop Rock Bottom Remainders shares the same name as the now-defunct rock band featuring several literary figures, including Stephen King and Dave Barry.
Homer and Marge's carpenter clothes slightly reference Mario and Luigi's (we mean Mario Bros.) outfits, except without the hat, gloves and moustache. Also the pants are patched and stitched and their sleeves are rolled up.
Marge's mailbox is based on architect Frank Lloyd Wright's Fallingwater, and Santa's Little Helper's new house is a replica of Westminster Abbey.
Seymour's quote "Eat shrimp and die" it's a reference to the phrase "Eat shlump and die" said by Duke Nukem in Duke Nukem 3D.
In this episode Bart is said to only be allergic to shrimp. In Blood Feud Marge lists Bart's allergies as butterscotch, imitation butterscotch, and glow-in-the-dark monster make-up (even though Marge wanted to cook Bart butterscotch chicken on A Milhouse Divided as a reward for only getting three cavities at the dentist), and Mommie Beerest and The Frying Game clearly show Bart eating shrimp without any adverse reactions. It is possible for allergies to randomly appear and disappear. He could have gained a shrimp allergy and lost his other ones. Furthermore, as shown in The Heartbroke Kid, Bart is allergic to cauliflower.
After all the workers leave on the roller coaster construction site, the camera points to Homer in the wagon thing. Behind him, the roller coaster looks completely repaired.
In Marge and Homer's bedroom, the floorboard broke and broke her nightstand. However, there never floorboards in their bedroom- it was green carpet.