Revealing mistake: When the phantom zone explodes it is a cheap pencil drawing animation.
Revealing mistake: When Luthor and Teschmaker are in the balloon, in the wide angle they both become coloured green due to the blue screen effect.
Revealing mistake: When Superman launches the Eiffel elevator in space and he flies back to earth, a white rectangle surrounds him where his image was superimposed to achieve the flying effects. (The Ultimate Collector´s Edition Box Set).
Revealing mistake: In Houston, when a man is thrown through a truck, notice the ground he falls on: The sand is leveled higher than the rest of the road around, obviously to hide a landing mat. Furthermore, after the fall the man turns around and he's got a bulgy square on the back to help for a safe stunt.
Revealing mistake: When Superman grabs the antenna above the pram, part of the antenna disappears because of the blue screen effects.
Revealing mistake: As Zod and crew blow people and objects down the street, it is obvious in some shots that they're all heading toward a painted studio wall.
Revealing mistake: As Ursa slams the man's arm down, the section of the table their arms hit has been cut to make the stunt possible.
Revealing mistake: As Non lifts the car to get the shotgun, the front of the undercarriage has a pile of dirt it, possibly to hide the lifting device.
Revealing mistake: The Cosmonaut Zod meets first pulls at his supply line. As he does, if you look closely the black wire used to make the hose move is visible.
Revealing mistake: As the astronaut that Ursa meets moves, the wires used to make him float are visible.
Revealing mistake: In a close-up shot of the kid falling into the falls, one can notice the kid is just a dummy. Notice how his face is a lot paler than it was before. (00:39:35)
Revealing mistake: The hole that Non and Superman go through is already patched, as it's a different colour from the rest of the pavement (either from previous takes or to allow the effect).
Revealing mistake: During the Marlboro truck scene, Zod's stunt double has very noticeably longer, darker and bulkier hair, plus a thicker beard.
Revealing mistake: After coming out of the Marlboro truck, Superman grabs Zod by his feet. When he sends him flying away, Zod's been replaced by an obvious doll.
Revealing mistake: In the first scene when the villains are at the console, you can see Ursa's nose disappear, then reappear when Non walks behind her, then it disappears again. (01:44:30)
Revealing mistake: There are two times in the New York battle when you can see the actors are being filmed in front of a screen: 1. when Superman kicks Non, Superman in on film and Non is hovering in front of the screen. 2. When Ursa is flying towards Non and Superman with the flagpole, she is hovering in front of the screen.
Revealing mistake: When Non and Zod break in through the White House window, a black strap is seen attached to each one's body to help them descend safely.
Revealing mistake: When Zod throws a man against the wall in East Houston, the man goes through the wall into a truck. Before he crashes against the truck, wires holding him are visible.
Revealing mistake: During the Metropolis battle, after Non and Super go down through the pavement, Non is launched upwards thorough the concrete. Check the people around, specially the cop on the right. They are blatant toys (note the cop's weird arms), revealing it is all a miniature set.
Revealing mistake: Before the villains change the faces on Mt. Rushmore, the original ones (which are a matte painting) have a greenish look. Definitely not like the real sculptures.
Answer: Superman was be able to kiss Lois in such a way that the heightened emotion wiped out her memory of his identity. To answer your second question, even though Lois promised not to tell anyone, Superman decided he does not want even her to know his secret identity.
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