In Squidward's art class, Spongebob makes a statue, at first the statue's left hand is on his face, but when the art collector is going to take the nose off, the right hand is the one on the statue's face then back again to the left hand.
Squidward shows the art collector one of his painting that the janitor throws away, then Spongebob finds it in the city dump. However, Spongebob leaves Squidward's art class and he gets carried away by the garbage truck before the janitor throws it away, meaning that the painting shouldn't have been in the dumpster yet.
When Mr. Krabs stubs his foot, he grabs it; then a moment later he grabs the other one.
In the scene where SpongeBob and Patrick play Eels and Escalators, you can't see the floral pattern on Patrick's shorts.
When Mr. Krabs hits his foot on the rock, he supposedly says all thirteen swear words. He uses the dolphin sound four times and the seal bark twice.