After the Road Runner crashes the old car into the stone wall the exhaust pipe at the back of the car is not attached to anything.
The robot clock is shown walking on the flat ground and then proceeds to walk over a few large rocks without falling over.
At the end of the cartoon Wiley is shot out into outer space by his rocket and Wiley looks back at a small Earth. But instead of this little Earth being surrounded by the blackness of space, it is surrounded a blue sky that fills all of the rest of the screen. Further, this blue sky is filled by many clouds which are not perpendicular to the center of the earth, but parallel to the bottom of the screen.