Continuity mistake: When they are in east Houston, Idaho, the helicopter gets knocked out of the air and lands upside down onto a jeep. You see the pilot get smashed into the seat of the jeep real hard and yet seconds later he walks away unharmed.
Continuity mistake: There must be a barber's shop or a cosmetics shop somewhere in the Phantom Zone. At the beginning of the first Superman film General Zod's hair looks as if it has been blow-dried, but all through Superman II he looks like he uses wet-look gel.
Continuity mistake: During the fight in Metropolis, General Zod is about to throw a wall part at Superman, it cuts to a street scene with people and there is a "no entry" sign reversed, showing the film was flipped for some reason.
Continuity mistake: Clark and Lois are undercover in a hotel in Niagara Falls investigating a Honeymoon scam. There is a scene where Clark is removing money from his pocket to tip a porter. You can plainly see that some of the money is falling on the ground. In the next scene the porter walks away with his tip and the falling money has disappeared.
Continuity mistake: In the opening scene where the three villains destroy the energy crystal and the lights go dark and the rings descend upon them, the light that surrounds them is shown coming down from the ceiling. But, when the dome opens, the light surrounding them shines up from the floor. (As also seen in Superman: The Movie.)
Continuity mistake: When Lois is falling on the elevator, the camera angle cuts between her reactions and the ground coming up quickly. When Superman arrives to save her, there is suddenly a LOT more distance from the elevator to the ground than there was just a moment before.
Continuity mistake: When the elevator falls down the shaft with Lois trapped underneath, Superman flies up to rescue her. He stops the elevator, and when he does, Lois climbs off from the bottom of the elevator and runs to hug him. Problem is, when she climbed off the bottom of the elevator, there should have been nothing but air underneath her.
Continuity mistake: When Zod is considering things on the moon, look at the shot of the Earth and the Sun behind him. First, there's apparently a lunar eclipse going on. You see the Earth on the Sun's right side. Then the camera pans over, and the Earth moves over to the Sun's left.
Continuity mistake: When Zod throws the shotgun after discharging it, it lands in front of the police car's back tyre. But when the dumb one goes to pick the gun up, it is now towards the back of the car.
Continuity mistake: In Niagara, Clark moves to the left to warn a kid from falling and a woman next to him lowers her camera. In next shot the camera is up and she repeats the previous movement.
Continuity mistake: Zod punches Superman and makes him fly backwards and crash against a metal structure. The wide shot shows him in the middle of it, but in the immediate close one, he is located on the right side.
Continuity mistake: In East Houston, after Ursa says "your general wishes to speak" a sudden change of light takes place and her face swaps from shady to very bright.
Continuity mistake: When the three super villains attack the astronauts on the moon, as Non lifts the lander's leg, there is a shot of the astronaut inside a collapsing cabin. It is like there is something crushing the roof inwards, but all three super villains are accounted for, with Zod sat in the moon buggy, Ursula standing next to him and Non lifting the lander. This happens twice in the space of a few seconds before Non jumps on top of the lander to crush it. (00:27:25)
Continuity mistake: After Non smashes Superman against a metal structure which gets totally crumpled, Superman stands up and the structure is undamaged.
Continuity mistake: When the TV camera focuses on Zod, there's a man crouching by a car behind him. Half a second later he is standing and leaning on the hood.
Continuity mistake: While Superman is crushing Zod's hand, there's a close-up of Non watching the scene in awe. In the following shot, Non's expression has changed to normal.
Continuity mistake: When Ursa throws the White House cop out of the window on the ceiling, the hole in the glass appears before he goes through it.
Continuity mistake: When Superman starts playing hide and seek with the villains, he stands away from the icicles. When Ursa shows up a frame later, he's leaning against them.
Continuity mistake: Before the villains arrive at the Daily Planet, Lois' hair is fluffy and her fringe has a straight cut. When the scene ends, her hair is shorter, and her fringe has some stylish cuts. Also, Jimmy's hair alternates between very short and long, due to Richard Lester's reshoots.
Continuity mistake: When Lois is trapped under the elevator, the wide shots show a thick metal bar close to her throat. In the closeups showing her head and shoulders the bar isn't visible.
Answer: In the theatrical cut, nobody really knows why the green crystal restored his powers. However if you watch the Richard Donner cut, it is explained that the green crystal is a communication device that helps Superman talks to the residual essence/spirit/ghost of his father Jor-El. Before he died, Jor-El gave the crystal to his son. Jor-El anticipated that Kal-El might give up his powers, and he also anticipated that Zod might eventually escape the Phantom Zone, so Jor-El lets his son absorb the leftover energy of his spirit, thus restoring all his Kryptonian powers.
Matt Van Gogh