Continuity mistake: When Chloe shows the newspaper to Jimmy with his photo on it. The photo is not the same when it is shown in the close-up.
Visible crew/equipment: When Lex is driving out of the dam and the police arrive, Lex exits his car and two crew members heads are reflected in the glass window of his door. (02:35:30)
Continuity mistake: In the scene between Martha and Clark near the end of the episode, the cut on Martha's forehead switches from above her right eyebrow to her left, and then back again. (00:37:40)
Continuity mistake: When Clark looks at Phillipe's police report, there is a photo of Phillipe facing sideways. In the next shot the photo has changed, so that now he is facing forward. (02:21:10)
Continuity mistake: When Zod/Lex pierces Lana's hand, he pierces it at the same level as Lana's head. But in the camera angle immediately following, Lana's head slide downs the wall and draws level with her hand. (00:20:05)
Continuity mistake: While Clark and Zod/Lex are fighting in the field, the blood on Clark's right cheek changes throughout the scene, from disappearing, to smudging, to thick blots. (00:30:00)
Continuity mistake: Lana was found shot in her upper left shoulder but at the end of the show she has a sling on her right arm. (00:42:00 - 00:43:05)
Other mistake: Lex picks up a chisel and stabs Clark in the side. It bounces off and out of Lex's hand. The last couple inches are bent and twisted. Chisels are made from extremely tough steel. But no matter how hard Clark is, Lex is not strong enough to exert the force necessary to bend the chisel itself.
Visible crew/equipment: Martha and Lionel are in the barn when everything starts to fall apart. The camera shot changes from them to a boat falling from the rafters. As it falls there is a visible production crewmember hiding next to the window, holding a hay bale. (00:28:15)
Continuity mistake: When Clark blows out the barn doors, they go out at a fairly low angle to the ground. But when they come down next to Lois they drop down straight out of the sky.
Suggested correction: The pieces of the barn and door blown off are on screen for a second or less and don't travel far enough on screen for you to predict their trajectory. They could have easily been moving upwards without being able to tell. The barn door travelled far enough that it would have risen higher into the air.
Continuity mistake: When the Phantom child kills the doctor and drags him over to the fingerprint scanner to open the door, we see the doctor has no glove on his hand when it is placed on the scanner. But when his arm drops to the floor, there is a glove on his hand now. (02:32:35)
Factual error: When Clark is on the roof, and Lionel calls him over to walk to his car with him, in the background as they walk, you can see a building which has the logo of a Canadian bank. Although set in Smallville and Metropolis, Smallville is filmed in Vancouver.
Plot hole: Clark is crippled throughout much of the episode due to there being kryptonite in the tunnels. At one point he gets a rock stuck in his arm and he bleeds from this wound. For much of the time after this he has blood running down his arm from this wound. After he gets out of the tunnel he is healed but the problem is the blood from the wound also disappears. The actual wound should have healed up but the blood from that wound should still be shown staining his arm.
Factual error: Chloe wants to access the security camera files on the Luthor mansion server to see what happened to Lex. She can't crack the password, so she says she'll just download the entire hard drive. She pulls out a thumb drive and proceeds to do so. Two big technical problems here. Firstly, if she can't log in, she can't access anything on the server. And Secondly, the entire hard drive for a server (which is huge) containing video files (which are huge) will not fit on any thumb drive.
Audio problem: When Noir-Lois comes out to sing, the microphone picks up her voice before she's anywhere close enough for it to do so. (00:52:30)
Continuity mistake: When Lana hands the gun to Jimmy, she hands it to him aimed away from her. When Jimmy takes it, it is aimed towards her. (00:59:00)
Continuity mistake: When Chloe and Jimmy find Lana shot in the elevator, there is a gun on the floor beside her, with a small pool of blood beside in the gun. In the next closeup shot on the floor, the small pool of blood is gone. (00:42:00)
Continuity mistake: When Chloe and Lois return to where the barn door landed, the shadows and sunshine keep changing between shots. (00:55:35)
Continuity mistake: When the barn door nearly hits Lois she is just jogging alongside a clear fence. But when she and Chloe investigate it later, there's a large gate there which was nowhere to be seen beforehand.
Continuity mistake: When Lois attack the guard down in the dam, she hits his face, which causes the black cap that the guard is wearing to begin to fall off. Yet in the next shot the hat is firmly back on his head, before it is completely knocked off by Lois' next hit. (02:23:00)
