When the children are singing the Camp Krusty song, Martin Prince can be seen in the group but Martin is supposed to be over in the next camp, Chief Starving Bear.
When Krusty is taken to Bart after the take over of the camp and they rip his shirt off, it shows him in one shot buttoning his shirt up. but then in another shot his shirt is unbuttoned and still torn up.
At the end of the episode, Krusty is shown to be comatose, with a bottle of tequila in his hand. The drink appears to have a worm in it. Contrary to popular belief, Tequila doesn't contain a worm. A worm is found in a spirit called Mezcal.
Ralph Wiggum's look and voice are very off model from how he would look and sound throughout the rest of the series.
During the countdown, when it gets to "2" you can clearly see the RED end of the oral thermometer, THAT end should be in his mouth.
Marge is seen sobbing at the dinner table, however when the camp krusty bus is going away Marge is seen celebrating along with the other parents.