Other mistake: After Clark sets down the picture of his mother, Martha, he clicks a button on his keyboard and the monitor for his computer shuts off. Only thing is the button he pressed is the one directly to the left of the Space Bar, which is the Alt button. I don't know of any computer where you press the Alt button, even in a shut down process, to shut the computer down or even just shut off the screen. (00:04:30)
Other mistake: After Dark Superman kills Toyman, someone calls Lois and tells her that. She answers the phone and says "Lane... HE DID WHAT!?" She responds to the news way too quickly. There wasn't even enough time for the person on the other end to say anything, much less inform Lois that Superman killed someone. (00:48:55)
Other mistake: After Dark Superman destroys the weapons of the cops that try to arrest him, he walks away down the sidewalk. As he does, there is a yellow vehicle on the side of the road. This vehicle is horribly drawn and does not make sense. There are no headlights, there are no doors, just one line down the center of the side showing some sort of separation between the front and back halves of the car. There is no hood, the front of the car being a solid piece. There are no side view mirrors. And the wheels are so small, you could hardly get them on a child's toy truck. There is also a very large orange square on the side by the bumper next to a fire hydrant that appears to be a blinker or reflector, but it is way too large. (00:51:15)
Other mistake: Before Lex can shoot Lois and Jimmy, Dark Superman suddenly shows up and cuts through his gun with his heat vision. The laser goes right through the gun, and Dark Superman made it powerful enough to cut through the metal of the gun. Yet the next shot shows Lex standing right next to a glass incubation chamber for a Superman clone, and there is no damage to the chamber at all, or the floor, or any evidence at all of the laser. (00:58:20)
Other mistake: As Dark Superman begins using his laser vision to destroy the room full of Superman clones, he cuts through them with extreme prejudice. The lasers visibly go through rows of chambers at one time. Yet when the bodies of the clone Supermen fall out, not one has any damage to them. The lasers passed right through the bodies. Some should have been cut in half, some in pieces. (00:59:00)
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.