Continuity mistake: While Clark is talking to the agent that he has pinned to the wall, with the billiard table, the balls near the gun change their positions between shots.
Continuity mistake: When the agent goes to the Luthor mansion and confronts Clark about Jessie's whereabouts, Clark uses his speed to push the billiard table into the agent and jams him against a wall. As he does, the billiard balls obviously move due to the force Clark put on the table. Cut to the agent and later on Clark and we still see the billiard balls on the table yet they are no longer moving. It was too quickly for an object in motion such as a billiard ball to come to a complete stop given the force Clark exerted on the table.
Continuity mistake: At the bar, the agent shows the barkeeper a picture of Jessie. Throughout the whole conversation, it is the agent who is holding the picture. However, when the agent says something about the legal drinking age in Kansas, it is the bartender who is instantaneously holding the picture.
Factual error: When Palmer is looking at the phone log, the wrong area codes are shown. Most of the list consist of the city of Topeka, with Wichita and Kansas City also seen, with a "206" area code. "206" serves the Seattle Washington area. The other area code seen is "620", which is a Kansas area code, but Topeka is in the "785" area code.
Continuity mistake: When Pete and Clark go to Byron's house to find him, Clark finds the hidden locked door to the cellar. Clark then breaks the locks and uses both his hands to pull on the door. Cut to a different angle (from above Clark) but now he is just using his left hand.
Continuity mistake: After Byron transforms, he pushes Pete through the windshield of an old car. The impact causes the front passenger door of the car to open. Yet later when Clark check up on Pete, the front passenger door is now closed.
Continuity mistake: Clark arrives at the Talon after Lex reads the mysterious love letter for Lana. Lex the gives back the letter to Lana twice between shots.
Continuity mistake: Byron mom buys him a book by Edgar Allan Poe at the used bookstore. Byron takes it with his right hand and looks at it. Cut to a wider angle (as Byron stands up) but now he is holding the book in his left hand.
Revealing mistake: When Lionel is playing the piano while talking to Lex, you see inside the piano and none of the dampers are moving for the notes he's playing, revealing he's not really playing or even hitting the keys.
Continuity mistake: When Lex has the envelope and pulls it away from Lana as she grabs for it, the flap is opened, so the wax seal is on top. In the next shot the flap is folded down.
Visible crew/equipment: When Martha and Jonathan are talking about Lionel's job offer in the kitchen, a boom mic can be seen in upper left corner of the screen.
Continuity mistake: As Clark walks into his grandfather's motel room, his hands are behind his back. He turns to face his grandfather and both hands are now in front of him holding the photo album. The next shot shows him in the foreground raising his left arm from his side to hold the album. (00:31:30)
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: Clark tells his parents that he went to see his grandfather and that he asks to give the cashiers check to his mom. He takes it out of his pocket with his right hand and Martha Kent takes it with her left hand. Cut to a different angle but now it is Martha's left arm which is see being pulled back to her body as if she took the check using her right hand instead.
Continuity mistake: At the Talon, Clark tries to write his essay when Crissy shows up asking Clark to sign up for the decorations committee. Crissy holds her clipboard with her left hand and places her right hand on her hip. But in the next shot Crissy's right hand on the clipboard as well. Cut back to the previous angle and her right hand is back on her hip.
Revealing mistake: In the Talon when Crissy is talking to Clark, we see a close up of her hand aging. However, as her hand ages, a reflection of her real hand (which supposedly aged) can be seen on the metal clip of her clipboard, which is still young and smooth, and not aged.
Continuity mistake: When Russell shows Crissy the lighting on the stage, we see him put a blue filament on the light with both his hands. He then drops his right hand as they cut to another angle but now he is lowering his right hand again.
Continuity mistake: When Clark arrives late for school in Lex's car, he is stopped by principal Reynolds who tells him that he should have been there four minutes ago and points at his watch with his right hand. Cut to a different angle but now he is pointing at Clark with his right hand.