In the first segment, they have a trial at the stroke of midnight, but a couple of seconds after midnight, when Lionel Hutz enters the room, it appears to be 10 to 2 on the clock.
In "Nightmare at 5 1/2 Feet," when Homer first blows the foghorn, Bart throws his spoon in fear. In the next shot, the spoon appears in his bowl.
In "Bart Simpson's 'Dracula,'" when Homer, Marge, and Grandpa find out Bart's a vampire, Marge enters the room by herself. In the next shot, Marge is holding Maggie.
When Vampire Bart is floating at Lisa's window, he is floating with Vampire Janey, Vampire Ralph, Vampire Milhouse, and Vampire Martin. When Bart smashes through Lisa's window, the other vampires are gone and are not seen for the rest of the scene.
The last piece of the doughnut Homer sold his ole to the Devil for, had purple frosting on it, however, when Homer pulls it out of the fridge later, it's bare.
The Philadelphia Flyers team colors are orange and white, not blue.