Continuity mistake: When Sylvester is looking through the window with his binoculars, he looks at Spike and you can see there is a bowl with a bone next to his kennel. But when Sylvester sneaks past Spike's kennel after entering the yard, the bowl has gone.
Continuity mistake: When Sylvester is testing the robot dog he has built, you can see there is a piece of paper underneath the radio control unit. In the next shot, the paper has gone.
Audio problem: When Sylvester is saying "Down, boy!" when the robot dog is attacking him, his mouth is not moving.
