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)
Factual error: Superman throws Doomsday through a small power grid in the middle of Metropolis and then Doomsday drags him back through it, nearly obliterating the plant completely. Yet with this power station destroyed, not a single building or street light in the surrounding area is affected by the sudden change of power flow. (00:22:20)
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)
Continuity mistake: After Superman saves Lois and Jimmy in the chopper, he and Doomsday get into a fist fight for a moment, Superman getting a few good hits off, followed up by Doomsday spinning and slamming Superman in the face with his elbow. The shot cuts to a different angle as Superman staggers away and falls, and suddenly the number of spikes on Doomsday's shoulder goes from 4 to 1. (00:22:00)
Continuity mistake: Having saved the chopper, Superman and Doomsday go at it again in the street. As they are punching, you can see buildings on the left side of the street, and in the distance there is a small blue building with yellow windows and a taller building beside it to the left with a large sign on top. It then cuts to a close up of Superman getting a good punch to Doomsday's face followed by Doomsday smashing his elbow into Superman's face, and suddenly another building appears between the small blue building and the other one, and the large sign has vanished off the building that was beside it on the left. (00:22:00)
Continuity mistake: Once Lois and Jimmy are out of the chopper, Doomsday bursts up from the rubble of the building and begins charging at Superman, who then charges back at Doomsday. As they collide, you can see down a side street at the buildings, several cars in the road, and some rubble. Doomsday and Superman bounce off each other and slide back in their respective shots, and then go at it again in a fist fight. The side shot then shows the same street, only now some of the buildings on the left side are noticeably different, the cars have vanished from the street, the smaller pieces of rubble in the road have changed around, and the street lines in the road have vanished. (00:21:55)
Continuity mistake: When Superman sets down the chopper, there is a building behind them with some people standing around. It cuts to a very brief shot of inside the chopper as Lois removes her seat belt and then cuts back to outside the chopper, and suddenly the people standing around have moved. Also the air intake on top of the chopper changes shape and goes from a lighter blue to darker blue. The damage to the windshield becomes more extensive between shots, the glass part on the bottom of the front of the chopper goes from being two parts to one solid part, and the broken landing leg changes from a light blue to being white like the body of the chopper. (00:21:25)
Continuity mistake: After Superman has set down the chopper, Jimmy and Lois step out and Jimmy places his hand on the chopper blade and begins to barf. But then the camera cuts to an angle behind Jimmy as he barfs and suddenly he is much closer to the tip of the blade. (00:21:30)
Continuity mistake: When Superman goes to set down the chopper that Jimmy and Lois are in after Doomsday trashes it, the air intake vent on the top of it is smaller than seen before. Then when he sets the chopper down and lets Jimmy and Lois out, the design of the intake vent changes completely. (00:20:45 - 00:21:20)
Continuity mistake: When Superman pulls Doomsday off the chopper, there's a metal panel stuck to Doomsday's fingers and you see it still there as Superman throws him away. Then the angle changes just before Doomsday smashes through the roof of a building but suddenly the panel has vanished from his fingers. (00:21:10)
Continuity mistake: Jimmy kicks the side of the helicopter where Doomsday is holding on and Doomsday falls, but then grabs the chopper by the landing bars. His left hand is forward of the metal piece that holds the landing bar to the frame of the helicopter as he uses his right hand to grab into the side of the helicopter. But then after Superman pries Doomsday's right hand away and goes to cut through the connecting metal with his laser vision, Doomsday's left hand is suddenly holding on behind the connecting metal. (00:21:00)
Continuity mistake: Jimmy zooms his camera in on Doomsday as the creature spots him and begins climbing rubble to jump at their helicopter. As Doomsday is climbing up, it cuts to a shot from behind him and suddenly the rock and the way he is standing on it changes. (00:20:30)
Continuity mistake: After seeing Jimmy and Lois in their helicopter, Doomsday leaps through the air and grabs it. The window of the chopper cracks and the frame where he grabs it bends with his grip and his weight. But then as Superman grabs Doomsday, a shot from the outside of the chopper shows the window and frame fully intact, no damage. (00:20:40)
Continuity mistake: When Lois spots Doomsday and Superman from the helicopter, Jimmy is beside her holding his mouth trying to not throw up. His camera is around his neck and you can see the button to snap pictures is on the right side of the camera at the top. But them moments later when it cuts back to them, Jimmy is holding his camera to snap pictures and suddenly the button has vanished off the right side, and his finger is on the left side as if he is pushing the button there. (00:19:50)
Continuity mistake: From the air, Lois spots Superman and Doomsday fighting below, and points. It then cuts to Superman and Doomsday battling by some rubble. Cuts to a close up and then back again as Doomsday smashes Superman into the ground, and now the pile of rubble behind them has changed. (00:19:55)
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.