Continuity mistake: In Kandor, Superman punches a hole in the ground and picks up a large chunk of the street out of the hole, but does not move from that spot. The shot changes to the robot's perspective of him about to throw the rock and shows his feet. The ground he just punched and picked up is in perfect condition at his feet. No hole, no cracks, no sign of the damage he just made.
Continuity mistake: Drones attack the Daily Planet. Jimmy and another guy push a desk at the drones and force them and the desk out the window with seamless precision. The next shot of the broken window shows that there is a 2 or 3 foot wall under it separating the window from the floor. The desk would have hit that wall and stopped and or crushed the robots against the wall, not magically hopped over the wall like it didn't exist.