Continuity mistake: At the beginning of the movie, Lois and Perry are arguing in his office, and you see his door. The handle of the door is on the right side. But 30 minutes later in the film when they are talking there again, the door handle has switched to the other side. It's most noticeable when Perry says "easy to lose sight of I guess in a world without Superman." And then takes a drink. (00:03:20 - 00:33:35)
Continuity mistake: When Lois and Perry are arguing in his office in the beginning, you can see his many plaques on his wall. Moments later when Perry is standing in his office door way talking to Clark, you can see the same wall and corner behind him. Now there are fewer plaques and they have moved around, most noticeably the round orange one now on the other side of the corner. Also the desk with books on it under the round orange plaque vanishes. (00:03:30 - 00:04:05)
Continuity mistake: As Perry White, the Daily Planet's Editor, picks up Lois Lane's report on Luthor's "charity organization", there is a blue mug visible next to his computer on his desk. The handle of the cup is facing to the right away from his computer. Moment later, the camera angle changes to being from the computer's left, and now the handle of the cup is pointing almost towards the computer. (00:03:30)
Continuity mistake: When Perry White picks up Lois' report, it is on the left side of the computer from his perspective. He keeps it in his left hand and does not move from that spot and the computer is shown in the next spot as being on the right edge of the desk. Yet when he slaps it down in the side shot, his arm and paper are suddenly to the right of the computer. (00:03:35)
Continuity mistake: As Lois is ranting to Perry White about her report, the door to Perry's office is behind her. You can see the writing of "PERRY WHITE EDITOR" on the door through the glass, backwards as it is on the other side of the door. The edge of the letters of the P in Perry and the E in Editor are about 3 inches from the edge of the window by my best guess. A few shots later, it cuts to outside this door showing Jimmy Olson eavesdropping on the conversation from the other side of the door. Now suddenly the letters are closer to the edge of the window, now being about only an inch. The font style of the text on the window also changes slightly. (00:03:40)
Continuity mistake: Behind Clark when Perry asks him about his flight, the elevator door is seen behind him with its green design lines all over it. Then after talking to Lois, he gets in the elevator and the door closes, and now the diagonal green lines towards the top have become much thinner. (00:04:00 - 00:04:50)
Continuity mistake: Clark is packing things from his cubicle when Perry first speaks to him. In the first shot of Clark, you can see the items on the desk of his cubicle, mostly the computer, which is very near the edge. When it cuts to a close up of him putting stuff in his bag, a cup full of pencils and pens appears next to his computer. Then as he is setting down the picture of his mother, the cup has more in it, and the things hanging on the wall of his cubicle change. (00:04:00)
Continuity mistake: When Perry White asks Clark if he shouldn't be on the way to the airport, Clark is putting a binder in his bag. His left hand is holding the bag and 3 of his fingers are balled up except his pinky. When it cuts to a close up of the bag, suddenly none of his fingers are balled, but all stretched out. The shadow of his right arm also appears on the side of the bag suddenly in the close up. (00:04:00)
Continuity mistake: Perry asks Clark if he should be packing for his flight and you can see the cubicle directly to Clark's right there are some brown papers of some sort on the wall of the cubicle. Then a moment later in a close up of Clark, the brown items have become a wall calendar. (00:04:05)
Continuity mistake: When Clark goes to pick up the blue lunch box next to his mom's picture, it shows his computer tower at his cubicle. On it above the red light, are two rows of 4 rectangles. Then it changes angles and now the first row of rectangles is thinner and more square shaped. Also between shots the extended gray space between the darker space where the rectangles are and the red light becomes thicker. (00:04:20)
Continuity mistake: After Perry White tells Clark to write articles when he's out of the country, Clark reaches over to his desk and picks up a purple lunch box with his right hand. His left hand has his bag in it. He then sees the picture of his mother, Martha, and reaches out with his right hand to pick it up and look at it. The lunch box is gone. He sets the photo back down and turns off his computer, and you see his left hand still holding nothing but his bag, and he turns to walk away. After he gets off the elevator, he suddenly has the lunch box again. (00:04:25)
Continuity mistake: Towards the beginning of the film, you see Clark pick up and then set down a picture of his mother down by his computer towers. Then 30 minutes into the film you see Lois look across over at that same picture after Superman's death and the computer towers change in design. (00:04:30 - 00:30:45)
Continuity mistake: At the Daily Planet, Clark picks up a picture of his mother and smiles at it before setting it back down. Between shots, the picture changes slightly, Martha's image becoming larger compared to her background. Most noticeably the window in the barn is closer to her head as well as the bush by her neck. (00:04:30)
Continuity mistake: Just before Clark walks up to Lois' desk to tell her he's off to the airport, you see a view of part of her desk as she's throwing papers away. You see her phone, and there is nothing else visible except the side of her computer as the camera pans up. Then after Clark goes to the elevator, a different angle of her desk is shown at her cubical. Suddenly the phone is in a different position, a pencil appears, and a yellow sheet of paper is hanging off the side that was not there a moment before and is wedged under the phone. (00:04:30)
Continuity mistake: As Clark is telling Lois that he's off to the airport to leave for Afghanistan, she is putting her report on Lex Luthor's "charity organization" in the shredder out of frustration at Perry White. There is a painting of a landscape on the wall behind the paper shredder, and there is a blue file cabinet next to Lois and the shredder. The file cabinet is about the same height as Lois while she's sitting. It cuts to Clark, and then back to Lois in a closer shot, and suddenly the painting on the wall has vanished and the file cabinet is much taller. (00:04:40)
Continuity mistake: Just before Clark is shown getting into the elevator at the Daily Planet, the light arrows above the elevator are shown as the down arrow lights up. It cuts to Clark getting in the elevator and suddenly there is a white bar between the two arrows. (00:04:50)
Continuity mistake: When the laser drill is first shown at Project Applecore, you can see a protective bumper like thing on the front of it colored black and yellow in the caution stripes. Two scenes later when it is shown again as the workers decide to breach the spacecraft, the bar has changed. The lines being thinner and more of them. It also appears to be a perfect rectangle the second time whereas it was lopsided the first time. (00:05:20 - 00:08:50)
Continuity mistake: When the laser drill at Project Applecore is first shown, it has open wheels. But once the workers discover Doomsday's ship, the laser drill is seen backing up, and suddenly it has fenders. (00:05:25 - 00:06:20)
Continuity mistake: In Project AppleCore, once the forklift goes by carrying a load, you see in the distance where Dr.Murphy is standing still looking at a wall. It cuts to a close up and suddenly she is walking from the same spot she was standing. (00:05:30)
Continuity mistake: When Dr. Murphy at Project Applecore begins mocking Lex Luthor, she begins walking towards another worker and 3 large balls of sweat appear on her face. The shot cuts to a close up of the male worker as she is walking up and suddenly the sweat has vanished. (00:05:50)
Answer: In the comic book, Doomsday was put in a strait-jacket, strapped in metal bondage and placed in a cube like metal prison buried deep in the earth. It took him centuries just to break the bonds, then spent more centuries just punching his way out. With earthquakes, volcanoes and other natural disasters those events could shift Doomsday's prison to the surface.