Continuity mistake: Superman grabs Doomsday and rockets upwards with him to save a little girl and to take the creature into space. When he first starts going up, Doomsday's arms are forced down at his sides, but slightly in front of him from the force. But when the shot cuts to a distance shot, suddenly Doomsday's arms are stretched up in the air like how Superman normal flies. (00:25:25)
Continuity mistake: Lois is reading a newspaper in her cubicle about the death of Superman, and there is a pencil on her desk on top of some papers. A few shots later when Perry White gets closer to her to tell her that Kent is probably fine, the pencil turns around facing a different direction, and the papers it is on move also. A stapler also suddenly appears next to her computer, and the brown book on the far end of her desk moves closer to her and turns around so the spine is facing the wall to Lois right and the pages facing her computer when it was the spine facing her computer first. (00:30:35)
Continuity mistake: After Lois and Jimmy settle down by some rubble to watch the fight more, Doomsday is shown picking Superman up by his head before he begins punching his gut. In that shot, Doomsday's right arm is straight down by his side, and also the bone spikes have vanished off his knuckles. It then cuts to a close up and suddenly Doomsday's arm is drawn back some behind his back, and his knuckle spikes reappear. (00:24:45)
Continuity mistake: After Superman is flung out of the subway and hits a building, then lands on the ground face down, Doomsday leaps out of the hole and you can see what appears to be a brown 80's SUV, or a truck with a camper, behind him next to some civilians. The camera angle changes a side shot of him as Doomsday turns his attention to the civilians and charges them, and now the SUV has vanished. (00:23:40)
Continuity mistake: When Superman is launched out of the ground from his fight in the subway with Doomsday, he smashes into a brown building with yellow windows. The windows on the left side of the building are in a tall vertical column, with several horizontal rows of yellow windows on the rest of the building. When Superman hits the building, you can see he hits between the area of two horizontal rows of yellow windows. But it cuts to a close up and suddenly he is lined up with one of the rows. (00:23:35)
Continuity mistake: Doomsday picks Superman up by the head and is about to start pounding him in the gut when Lois and Jimmy run up to some rubble behind the creature and duck down. Jimmy then raises up his camera to his face to snap a picture, but when it changes to a shot from behind Jimmy and Lois, suddenly his camera is back down. (00:24:40)
Continuity mistake: After Jimmy takes a picture of the hole in the ground above the subway station, the shot pulls back and shows the hole, with several people gathered around it and some cars. Then suddenly some of the road is pushed up from Doomsday and Superman fighting below and the people turn to look. The angle then changes before more road is pushed up on the other side of the hole, and suddenly the part of the road that was pushed up in the previous shot is back down to normal, the green cars have vanished and a white one appears next to this new pushed up spot, and a guy wearing a white shirt suddenly appears where the road is pushed up. Also the crosswalk lines once again vanish. (00:23:35)
Continuity mistake: When Doomsday backhand slaps Superman down the tunnel, Superman skids along the roof for a moment first, and leaves a good amount of damage to it in the process before he falls to the rails below. But then when the subway train is coming and Doomsday turns his attention to it, the damage Superman made to the roof of tunnel has completely fixed itself. Also some of the lines at the start of the tunnel dividing the different concrete slabs have vanished. (00:23:10)
Continuity mistake: Once Doomsday slams Superman down through the ground into a subway station, he has him by the neck against the floor, and then clasps his other hand around Superman's neck. When he does, Superman looks up at him with his eyes just before he blasts Doomsday away with his laser vision. But his head is still turned sideways. It cuts to a different angle and suddenly Superman's head is fully facing up towards Doomsday. Also the grip in how Superman and Doomsday are holding each other changes a bit, notably with their hands. (00:22:45)
Continuity mistake: Doomsday leaps into the air and smashes Superman down into the ground, crashing down into a subway station. As they are hitting the floor, you can see the brown columns holding up the roof are almost to the edge of the walkway by the tracks and touches where the tan area of the floor changes to a light green color at the end. But then Superman shoots Doomsday back with his laser vision and Doomsday looks at him angrily, and now the columns have a good few feet between them and the edge of the walk way. (00:22:40)
Continuity mistake: Doomsday and Superman leave a sizable hole in the roof of the subway station as they slam in through the streets above. But when Superman throws Doomsday down onto the tracks, the shot shows the same spot where they made the hole coming in, only now the roof is devoid of any damage and the hole entirely gone. (00:22:55)
Continuity mistake: Once Superman throws Doomsday down onto the subway tracks, he flies at him and Doomsday back hand slaps him hard down the tunnel. Superman lands on his face on the rails, and you can see the sleepers on the ground under the rails. When the camera changes angles as Doomsday approaches him, the sleepers suddenly become much larger. (00:23:05)
Continuity mistake: Just before Doomsday ploughs through the fence of the power station carrying Superman with him, you see down the street he is about to go on that there is a yellow 18 wheeler with gray trailer and an pinkish car on the left side of the street. But then it cuts to a close up of those same vehicles as Doomsday steps on one to jump, and suddenly both have turned into green cars. (00:22:35)
Continuity mistake: As Superman is throwing Doomsday at a small power station, you can see several cars out in front of it on the two lane road. Notably on the left side a small truck in the middle of the road, that's not moving at all, and a small pink sedan car right on the edge of the sidewalk. But only a few seconds later as Doomsday runs through the fence back in the other direction carrying Superman, suddenly the truck has vanished, and the pink car has changed to a brown station wagon and is facing the other direction. The two lane road is now a three lane road, and the sidewalk next to the fence is suddenly much more narrow. (00:22:15)
Continuity mistake: After Superman blasts Doomsday away from him in the Subway station, Doomsday grabs him by the leg and flings him to the other side of the tunnel, breaking a large hole in the wall. As he hits, you can see there is a subway exit on the same wall about a yard or so away from where Superman hits. But then when Doomsday leaps at him to continue his attack, the wall is suddenly solid where the exit once was. (00:22:50)
Continuity mistake: When Superman throws Doomsday through a building, Lex Luthor is shown watching from his office from an over the shoulder view from his perspective. It then cuts to an angle from further behind him and suddenly an antenna appears on the building, and the design of the windows change. (00:22:10)
Continuity mistake: Jimmy and Lois walk up to the hole in the ground left from where Doomsday smashed Superman down into the subway. Jimmy holds up his camera and takes a picture, then it cuts to a close up of them. Suddenly his right hand goes from holding the side of the camera to holding the lens, and the strap of the camera is suddenly over his arm. Lois and Jimmy are also suddenly closer together, and her arm goes down to her side. (00:23:30)
Continuity mistake: After Superman recovers from getting elbowed in the face, he knees Doomsday in the chin and then flips over him and throws him hard at a building. But if you watch closely, the building it shows him being thrown at is different than when it cuts to the next shot to the building he hits and goes through. In fact it the building he hits looks more like the building off to the left of the one that he was thrown at. (00:22:05)
Continuity mistake: As Superman tackles Doomsday out of the way of the subway train, you can see that Superman grabs him from behind and is pushing him towards the wall, Doomsday facing it. But then it cuts to a different angle just before they hit the wall and suddenly Superman has Doomsday by the front and Doomsday's back hitting the wall. (00:23:15)
Continuity mistake: After getting hit by Doomsday's elbow, Superman hits the ground and slides across the road on his face, mostly his chin with his arms flailing around behind him. It cuts to a different angle and instantly Superman has pushed up off the ground with his hands and is rolling over. (00:22:00)
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.