Continuity mistake: In a wide shot of the corridor when Bugs is running away from the red monster, you can see there is nothing on the wall by the door. When Bugs runs into the door, two wooden beams have appeared.
Continuity mistake: When Bugs strikes the wall with a mallet, the wall crumbles and the red monster falls to the ground. At this point, you can see the mallet is by Bugs' feet, but when we see him in the next shot, the mallet is nowhere to be seen.
Continuity mistake: When the red monster (dressed in knight's armour) gets hit by Bugs' locomotive-style knight-riding horse, he crashes into a wall to turn into a can labelled "Canned Monster." At this point, you can see the can is in front of a plain brick wall, but when we see Bugs looking at the can in the next shot, a purple curtain suddenly appears.
