Immediately after taking part in the "Milhouse likes Lisa!" group taunt, Janey says, "He does not." And immediately after taking part in the "Janey likes Milhouse!" taunt, Üter says, "She does not!"
When Jimmy the Scumbag is being arrested and placed in the cop car outside the Kwik-e-Mart, the red and blue lights on the car switch sides between shots.
When the police arrest Jimmy the Scumbag outside the Kwik-e-Mart and put him the car, the red and blue lights switch sides.
Nelson's guitar playing is all wrong. First off, the guitar is seemingly strung upside-down (which would render it a left-handed guitar, except he plays it right-handed). When he strums upward, the sound is that of a downward strum and vice versa. Also, despite having a capo strapped to the neck a few frets in, he forms the chords with his left hand on the wrong side of the capo. He has his hand between the capo and the headstock, which in reality would have no effect whatsoever.
When Nelson thought the love note was from Milhouse and beats him up so badly, Milhouse ends up having to go to the hospital. Nelson was able to stay in school and be free. Nelson would've most definitely been expelled from school and arrested.