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.
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.
Continuity mistake: During the flashback that happens at the Luthor mansion, the one that starts with the cup shattering on the floor, young Lex is shown peeking through a slightly cracked open door. Just after Lionel asks the nanny to give him Julian there is a shot of Lex peeking in and you can see that he has hair on his forehead. Now Lex, at this point, would have been bald, as a result of the meteor shower in Smallville for several years and would have no hair at all on his head in this flashback. In fact when Lionel finally realizes that Lex is outside the door we see that Lex has no hair on his head.
Suggested correction: Lex is bald but still has eyebrows. There's never a shot of young Lex with hair on his head. You never even see his head when he's peeking, but you do see the hair from his eyebrows.
Continuity mistake: The first time Seth tries levitating a spoon, he floats it a few inches towards him. When Lana enters and breaks his concentration, it falls back down almost exactly where it had been.
Suggested correction: Even though it's impossible to tell how much the spoon moves towards him, the spoon was in the middle of the jello, then lands in front of the jello, a few inches away from the middle.
Revealing mistake: After everything with Dawn is over Clark goes back to the prom. Clark asks Lois if she wants to dance. Lois says "I'm not the one you want to dance with." and she nods to the door. The shot switches to show Lana walking in to the prom. When Lois makes her nod to the door Lana would have been completely out of sight. Lois nods before Lana even enters the room.
Suggested correction: We never see Lana walking into the gym. She's just standing at the door, nervous about going in. We don't know how long she was standing there. Not to mention the fact that the scene of Lana at the door could have happened at the time Lois was making her comment and Lana walked in before the first time we see Lois look at the door, before she nods.
Factual error: Tate fires at Clark, who is dressed as the drifter, 8-9 times from a revolver that is chambered for only 6 rounds.
Suggested correction: I count 5 shots fired, which is how he had 1 left that he was planning on using on himself. You must be counting ricochets or other sounds as shots fired.
Revealing mistake: When Clark throws the two villains against the brick wall at the end, it very flexes as though made of foam rather than brick.
Suggested correction: The guys aren't thrown against a brick wall. They're thrown against the side of an old wood shingled shed.
Other mistake: Krissy's mutant aging reduces her to dust and ash within seconds. Oddly enough, it takes her non-mutant clothing with her. (00:36:45)
Suggested correction: First off, we don't know what gave her powers, there's nothing to indicate a mutation. Second, we see beams of light or heat shooting out of her, indicating she's more than just rapidly ageing like her victims. Her body seems to be burning, turning her and her clothes to ash.
Continuity mistake: When the mirror falls on Lana and shatters on her, you can see that there are bleeding cuts on the left side of her face. However, for the rest of the episode, there are no cuts on the left side of the face (where they should be) but there are cuts on the right side of her face.
Suggested correction: When the mirror falls, we only see her left side. But in the hospital you can plainly see both cheeks were cut up, the right one a bit more. Throughout the episode though, the cuts on the left side never disappear and there just seems to be more shots of her right side when she's out of the hospital.
Continuity mistake: When there is a flashback of the shooting, the police officer is heard to fire 3 shots, yet in each other flashbacks it's 2 shots and there are only 2 wounds in the victim.
Factual error: Clark huddles over Krypto to protect him from the blast of the exploding van. He does not cover Krypto's head before the blast of fire hits them yet Krypto shows no sign of damage. At the very least the fire should have singed his fur.
Other mistake: Maddie and her father can control only glass, but when at the Talon he uses his powers to pull the diamonds out of the stained glass. Diamonds aren't glass.
Suggested correction: This may not necessarily be true by the way their powers work. Remember, diamonds are a form of rock that are clear. Glass is made from melted sand, which is a ground up type of rock that becomes clear. The similarities between diamonds and glass are enough that it is possible they could still do this.
Diamonds are compressed carbon, not a form of rock. Glass is melted silicon. They're both clear materials, that doesn't mean they're equivalent, otherwise they'd be able to control clear plastic or any number of other things too.
If more explanations of their powers were discussed in the show, one might be able to conclude they do or do not have power over diamonds. However, the script only states they have power over glass, they show no propensity for power over sand itself, or other rocks and minerals. As scripted, this remains as error as it go against what is established.
Visible crew/equipment: When Lex and Chloe are talking after the morgue, you can see a crewmember passing behind her at 30:53. (00:30:53)
Suggested correction: You see a person walk behind her in a corridor. Since it is very obvious and occurs during a short cut where nothing else is happening, it is deliberate. A fundamental rule on film sets is that once "action" is called, no-one moves if they don't have to. If a crew member had walked through the shot like that, they would have done a new take or just use a different segment of the shot.
Continuity mistake: When Chrissy kisses Troy in the beginning on the episode, it takes him a few minutes to age and die. Later in the episode, she kisses Russell and in a matter of seconds he is old and gray.
Suggested correction: When she kisses Russell, she kisses him longer than she did Troy. We even see him age faster the longer she kisses him, indicating the length of time she spends absorbing someone's youth, the faster they age and die.