Revealing mistake: When Lana has her nightmare, she wakes up in a room and discovers various people on pedestals, underneath body sheets. During the scene, some of the people under the sheets can be seen lightly breathing, although everyone under them is dead.
Factual error: When Lionel is leaving the prison, there is a bus unloading convicts as he walks past. No prison in the world would ever unload inmates and release an inmate in the same area at the same time.
Continuity mistake: When Clark and Alicia are talking by the ice rink, the way Alicia holds her red cup of hot chocolate keeps changing between cuts.
Continuity mistake: After Clark heats up Alicia's cup of hot chocolate with his heat vision, the steam coming from the cup is thick and rapid in the first shot, but in the next shot hardly any steam is coming from the hot drink.
Factual error: Alicia gives Clark the necklace with red kryptonite and this causes him to break Alicia's bracelet a few shots later. She then is able to teleport once it is removed. Now, according to the story, that bracelet prevents her from teleporting by releasing 'trace' amounts of lead into her bloodstream. If that were the case she would have to wait until the trace amounts were cleared from her system to start teleporting again.
Suggested correction: The way her powers work is unknown. Her body may be able to quickly remove trace amounts of lead from her body, which is why she would need to constantly have trace amounts put into her bloodstream.
Revealing mistake: Clark uses his heat vision to warm up Alicia's cup of hot chocolate. When the drink is hot enough to start giving off steam, the "steam" is not water vapor. Water vapor would be nearly clear and rise straight up from the cup. This "steam" is more likely from a piece of dry ice as the vapor is rolling over the side.
Audio problem: Clark is upset over the death of Alicia and is in the barn loft bouncing a ball off the wall. His parents come up and Jonathan sits next to him and tells him that what happened was not Clark's fault. The very next shot shows Martha sitting down and you hear Clark throw the ball again but you can see that his hands never make and motion to correspond with that action.
Continuity mistake: Alicia's hair keeps changing as Clark holds her in his arms. In some shots the hair on her right side is messy. When the shot switches to a close up, her hair becomes neatly combed and tucked behind her ear. All of this occurs after Clark burns the rope she was hanging by.
Revealing mistake: When Jason breaks into the bathroom to rescue Lana we see a shot of the shower from Jason's POV. In that shot you can see the steam is coming from the other side of the tub and is flowing up and in. If it had been actual steam it would go from inside the tub out.
Continuity mistake: As Clark and Geoff are driving, the first shot of the SUV as it comes around the corner shows the ground is wet and the wipers are going. During their conversation the windows are constantly being rained on. Geoff points to the stadium and they arrive a few minutes later and as they drive into the garage you can see the street is dry.
Continuity mistake: After Lois and Clark find out that Cooper dies, and after Lois leaves, while Clark and Geoff talk about how Lois is trouble Geoff hair keeps going from neat to slightly messed up. When the camera is behind Clark, Geoff's hair is all shaggy on the left side of his face. When the camera is behind Geoff, his hair is fixed so that the loose strands are tucked behind his left ear. These changes repeat throughout the scene.
Factual error: While Clark is standing on the field at Metropolis University at the end of the episode the shot pulls back to show the entire field. As it does there are two 50 yard lines visible and the goalposts in the wrong position because it's a Canadian football field, but Metropolis University is in Kansas.
Factual error: Clark finds Lois in the sewer and decides to use his heat vision to destroy the lock of the gate that is separating them. Clark uses his heat vision on the lock and the lock explodes, this is a very minor explosion. It also causes the door to fly off the hinges. Now the explosion from the lock is odd since heat vision causes things to melt and not explode, but Clark wasn't even using the heat vision on the hinges and they are destroyed. This is inconsistent with how his heat vision has been shown to work before.
Other mistake: When Clark is in the girl's room and a noise comes from the closet, Clark uses his X-Ray vision to see there's a person in there because he can see the skeleton and is surprised to see it's Lois when he opens the door. However, it's been shown before that Clark can use his X-Ray vision to see objects and people through solid objects. He should have been able to see that it was Lois rather than just a skeleton of an unknown person.
Other mistake: In episode 4-14: "Krypto," Genevieve tells Jason that the heirs of a 17th century woman named Gertrude are in danger. She then tells him that they themselves are "Gertrude's ancestors." But she must mean descendants, which means the opposite of ancestors.
Continuity mistake: After Lois hits the dog, she exits her car and runs to the dog. As she passes the back of the car, her tail lights are off. When she reaches the dog, her tail lights are on.
Visible crew/equipment: As Jonathan is being attacked by Hercules you can see that Jonathan, or his stunt double, has on a arm cuff that is used for protection of attack dogs.
Continuity mistake: Clark goes to see Lex about the dog. Lex, who was about to start a game of pool, breaks a fresh rack. Lex then goes to make his second shot from near the side pocket and as he does you can see there are two striped balls near the rail close to Lex's cue stick. Just after he takes his shot those balls are gone even though those balls had not been hit.
