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)
Continuity mistake: As Lois is starting up the helicopter with Jimmy, you can see the seats behind them and how they are designed, lots of lines and not plain, with the seat belts coming out about mid way down. But then as the helicopter is zooming by the camera, you can see now the seats are now plain looking, and the belts come out much higher up. (00:19:20)
Continuity mistake: Doomsday throws Superman at a building and he slams near a window, people looking out. It cuts to a close up as Superman falls to his knees and the people in the window suddenly change around. (00:19:05)
Continuity mistake: Once Doomsday is frozen, you can see that behind him where the tank is are a van and a car. But a little while later when Doomsday throws Superman down the street, Doomsday charges Superman and you see the tank and the van behind him, but the car has vanished. (00:18:20)
Continuity mistake: After Superman lands a couple punches on Doomsday, the creature grabs his fist and throws him down the street. As he hits the ground, you see a burning car behind him that is orange. The it cuts to a close up of Superman skidding and then getting up, the car behind him turns blue, and the damage to it changes. (00:18:45)
Continuity mistake: After Superman pushes Doomsday away once he breaks from the ice, Doomsday charges again, swinging a punch which Superman jumps aside to avoid. In that shot you can see the tank next to them and the .50 cal gun mounted on top of it. Then Superman retaliates and lands two hard punches on Doomsday and the camera cuts to a side angle, and suddenly the .50 cal has vanished off the tank. (00:18:40)
Continuity mistake: When Doomsday is first charging at Superman, Superman begins blowing at him to freeze him and you see this as a shot from behind Superman. There are no cars in the street between him and Doomsday. But once Doomsday is fully frozen and Superman stands there looking at him, the shot switches to showing them from behind Doomsday, and suddenly there is a car and a van on the sides of the street. (00:18:05)
Continuity mistake: Once Doomsday is frozen, a shot from behind him shows a van behind him partly covered in ice from Superman's breath. The back side window is a full glass window. Then a little later after Doomsday breaks free and Superman pushes him back, suddenly the side window is a solid metal piece. Also the ice on the ground becomes thick snow suddenly and the van's door handle disappears. (00:18:30)
Continuity mistake: The tank Doomsday throws at the soldiers is damaged badly and the cannon is bent down, and very visible when Superman catches it and sets it down. But then after Superman freezes Doomsday, you can see the tank behind him, and the cannon is no longer bent. (00:17:55)
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