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: 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: 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: 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: 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: 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: 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: After Doomsday and Superman get out of the subway, Superman flies into him before the monster attacks more civilians. But Doomsday counters and smashes Superman into the ground. Superman is then trying to get up and is on his hands and knees. But the angle changes and suddenly he is on his side. Also the car beside Superman vanishes between shots. (00:23:45)
Continuity mistake: Doomsday has a bone spike protruding up from each of his 4 knuckles. But when Doomsday grabs Superman by the head and draws back to punch him hard in the face, the spike on his thumb is missing. Superman catches his fist, and in that shot you can see two more of the spikes have vanished, and Doomsday only has one over his middle knuckle. (00:23:55)
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 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: Doomsday grabs Superman and pounds his gut hard enough to splatter blood on Lois' face. In a side shot of her and Jimmy, the blood streak on her face has two drips on it, and is curving up. It cuts to a close up of her, and suddenly there is just one drip, and it is curved down. Her mouth is also suddenly closed. (00:25:05)
Revealing mistake: Doomsday drops Superman once he hears a little girl crying and walks up to her to try and smash her. As he is walking up, it shows a close up of the crying girl and she is wearing a pink shirt with denim overalls on. But look closely and you can see a mistake in how she was drawn. The straps of the overalls are incomplete and stop a few centimeters away from the buttons on them that are supposed to hold the straps in place, and the buttons are between the straps and her overalls, with a gap between the buttons and the front part as well. It's not connected at all and should be falling off her. (00:25:15)
Factual error: Doomsday sees a little girl crying in the street and stops his assault on Superman to go attack the little girl. Superman quickly grabs Doomsday around the waist and jumps, rocketing them both up into space before Doomsday can crush her. The shockwave of this jump is seen as the tremendous force causes the street they were standing on to break apart and rubble fly. Yet the little girl is completely unaffected by the shockwave, it passes right through her and she is only feet away from the crater now left from Superman jumping up with Doomsday. (00:25:20)
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: After the big impact of Superman and Doomsday, Lois and Jimmy run up to the crater and see Superman's cape torn and tattered, hanging on a pole. As they run up, Jimmy is on her right, and she is has her body turned to the right when they stop. The camera cuts to show Superman's cape and suddenly she has her body turned to the left. (00:26:35)
Continuity mistake: When Superman emerges from the smoke and rubble after smashing Doomsday down with reentry, he is mortally injured and his suit is tatted, torn, and burnt. The shoulders are notably torn and his left shoulder looks burnt. Then after Superman dies in Lois' arms, the camera pulls back and suddenly his suit is in perfect condition, aside from the missing cape. (00:26:45)
Continuity mistake: As Superman is emerging from the smoke after the impact, the amount of damage to his suit on his right shoulder changes between shots of him, the close up of Lois and the back to him. The damage on the chest area also changes from appearing near perfect to very jagged. And the blood dripping down from his mouth also becomes thinner. (00:26:50)
Continuity mistake: At the start of the scene showing Superman's funeral, there is a yellow guard rail around the memorial stand with his coffin in front of the podium. Standing in front of the yellow rail are 13 police officers in full uniform, 7 on one side and 6 on the other. The shot cuts to the audience for a moment, and then shows the podium and memorial again from a distance shot, and suddenly all the police standing by the coffin have vanished. (00:28:10)
Continuity mistake: After Superman's funeral, Lois is sitting in her cubicle at the Daily Planet reading a newspaper. When Perry White walks up and talks about there not being word from Clark Kent, it cuts to a shot from further back. Some of the papers on the wall behind her vanish, the pencil on her desk vanishes, the papers pinned to her bulletin board to her right change shape slightly, especially the one towards the center bottom becomes straighter instead of crooked and longer, also displaying different text. And the distance between the edge of her bulletin board and the other cubicle wall increases. (00:30:15)
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