Continuity mistake: In the first shot it is seen, the fence of the power station that Doomsday is thrown at shows that gate part is slightly taller than the rest of the fence and has one sign on each door of the gate. But then moments later as Doomsday is plowing through the gate, it is now the same height as the rest of the fence, and only one sign is present, which becomes smaller and a darker color. Also two vehicles appear behind the fence that were previously not there. Also on the gate there is a sign on each side of it, but before it breaks there is a sign only on the right side. (00:22:30)
Continuity mistake: When Jimmy is looking at the newspaper in the ally with Lois, there is a small trashcan behind him. It's an olive green color and is dented. Then after he throws the paper at Lois and begins to walk off, the can is now gray, larger, and no longer dented. (00:45:40)
Continuity mistake: Doomsday has a bone spike protruding up from each of his 4 knuckles. But when Doomsday grabs Superman by the head and draws back to punch him hard in the face, the spike on his thumb is missing. Superman catches his fist, and in that shot you can see two more of the spikes have vanished, and Doomsday only has one over his middle knuckle. (00:23:55)
Continuity mistake: When Doomsday slams Superman down into the subway, the hole they make in the street is right in the middle of a crossing. But a minute later in the film as civilians are walking up to the hole, there are no lines anywhere around it. Moments later after Jimmy takes a picture of the hole, the shot cuts to a far angle and now the hole is next to the crosswalk lines, and in that shot the stairway entrance to the subway station also vanishes. The road also becomes much wider with more lanes, and the red truck turns around. (00:22:40 - 00:23:25)
Continuity mistake: In Metropolis on the bridge, Doomsday grabs a soldier and breaks his neck and skull. In that shot, the soldier's arms are inside Doomsday's hand and his hair is a light brown or gray. But then when the shot changes as Doomsday begins to throw the soldier to the side, the soldier's arms are suddenly outside of Doomsday's hand, and his hair is now black. (00:17:10)
Continuity mistake: After Superman rescues Lois from Toyman, he is flying her back to her apartment. She is marveling at how he could be back and places her hand on his cheek, with her wrist going over his chin as he frowns. It cuts to another angle, and suddenly her hand has moved back some and her wrist not over the front of his chin. And Superman is suddenly smiling. (00:39:10)
Continuity mistake: A black cop thanks Superman as some white cops lead away Toyman. Then Superman lifts off to fly away and a shot from a different angle shows the black cop suddenly vanishes. (00:38:45)
Continuity mistake: The day after his ‘resurrection', Superman is standing in Lex's office looking for him. Behind him in the high shot, you can see Lex's desk with a computer monitor close to the center in front of the chair. It then cuts to an angle in front of Superman and pans across the same desk, and suddenly the computer monitor is twice the size and right on the edge of the desk, a second monitor appears on the far right of the desk, and the armrests on Lex's main chair vanish. (00:40:40)
Continuity mistake: Before Lex shoots Tess, you can see there are two computer monitors on his desk. In the silhouette shot when he blows her brains out, suddenly the leg of the desk is much closer to the monitor on the right. (00:34:55)
Continuity mistake: When the doll leaps at Lois with a knife, she grabs one of three reddish pink backpacks and smacks it into the window. The back pack she grabs is the one on the left, and as she grabs it you can see that the middle backpack has a rectangular shape on the front that is just an outline, and the backpack on the right has a similar spot but is round and yellow. Then when the children are getting off the bus, the remaining two backpacks are shown hanging there still and the one that was in the middle now has a yellow oval shape on the front instead of the rectangular outline. The design of the backpack is also different. Also in the shot just before this, the same spot is shown, but the backpacks are missing. (00:36:35)
Revealing mistake: When Lois looks in the driver seat of the bus, there is a mechanical doll there that turns its face towards her and holds up a kitchen knife. The doll has a missing eye, and this is shown in the reflection on the knife. But the crack that is under the hole where the eye is missing is not fully reflected. (00:36:20)
Continuity mistake: When Lois is sneaking up on the bus, you can see there are several pipes on the roof of the building they are on sticking up all around. But a little later when Toyman is lifting the school bus with the spider, the roof is visible behind it and the pipes are gone. (00:36:05 - 00:37:30)
Continuity mistake: Once the police begin driving away after Toyman's threats, the camera pulls back showing Toyman's spider holding the roof of the bus, and you can see the two legs are puncturing the top of the bus. It then cuts to a front view of this and suddenly the top of the bus is without a scratch, and the shadows on the roof of the bus move further down. (00:36:00)
Continuity mistake: After hugging the money, Toyman moves his giant spider mech back on top of the school bus and then tips it over the side of the building while threatening Metro PD to back off. He is using the left side of the spider to hold the bus, and the legs on the right side of the spider to stay on the roof of the building. You can see in that shot that 4 of the right legs are on the roof behind the small wall. But after a brief moment of cutting to Toyman's face, it cuts to show a shot behind the spider before Lois opens the door and suddenly the front most of the right legs of the spider is hanging off the building. When it shows the front view of the spider again, the legs are once again all behind the wall. (00:35:45)
Continuity mistake: As Tess and Lex are talking in his office about how Lex was cheated out of his winning strategy by Doomsday, the arm rests on his chair are square. But then when the camera pans back up after he shoots Tess in the face, the arm rests are now rounded and bigger. (00:35:00)
Continuity mistake: After Perry White says that Jimmy is weak and is not strong enough to hold onto his ideals, he turns around his chair and holds up his glass. It then cuts to a close up of his face just before he takes a drink and suddenly his fingers are holding the glass much higher up. (00:34:00)
Continuity mistake: After Jimmy quits the Daily Planet, Lois barges into Perry's office demanding to know why and discovers that he is drinking. One shot shows him tip up his glass and drink most of the contents, leaving only a small amount with the four ice cubes. It cuts to Lois for a moment then back to Perry as he says to not sugar coat it, and now his glass is half full, when he nearly emptied it moments before. (00:33:50)
Revealing mistake: An electronics shop has TVs on display, all showing a newscast about rising crime rates in Metropolis since Superman's death, and the window is broken by a brick as some thugs start stealing the TVs. Watch closely as they pull them out, the TVs have no power cords, but are on. Most noticeably on the second one when the guy has the TV lifted up, no cord seen, and yet the image still displays on the TV until he pulls it out of the window. (00:33:05)
Continuity mistake: After Superman's funeral, Lois is sitting in her cubicle at the Daily Planet reading a newspaper. When Perry White walks up and talks about there not being word from Clark Kent, it cuts to a shot from further back. Some of the papers on the wall behind her vanish, the pencil on her desk vanishes, the papers pinned to her bulletin board to her right change shape slightly, especially the one towards the center bottom becomes straighter instead of crooked and longer, also displaying different text. And the distance between the edge of her bulletin board and the other cubicle wall increases. (00:30:15)
Continuity mistake: As Superman is emerging from the smoke after the impact, the amount of damage to his suit on his right shoulder changes between shots of him, the close up of Lois and the back to him. The damage on the chest area also changes from appearing near perfect to very jagged. And the blood dripping down from his mouth also becomes thinner. (00:26:50)
Chosen answer: When they call Doomsday a machine, they don't mean a literal machine. Just that he was built/designed. The comics were much the same. Doomsday was created by placing a baby on the most dangerous planet in the universe, and cloning that baby every time it died, forcing it to adapt. Doomsday eventually escaped this torture.
MasterOfAll