Continuity mistake: When Bugs performs his "Invisible Shield" gag, he puts a bucket in a hole in the frozen lake. The hole was not there when first saw Bugs at the lake.
Audio problem: When the Big Bad Wolf is blasted through the wall a second time, we cut back to Bugs who says "I don't see why anybody thinks these club initiations are dangerous." When he says it, the audio is a few frames behind his mouth.
Continuity mistake: When we see a close-up of the meter, there is a box saying "10 Centavos for One Hour." The words were not in the box in the previous shot.