Continuity mistake: In the kitchen, Martha collapses and Clark catches her just in time. Jonathan then rushes to his wife and puts his right hand on her cheek and his left hand on Clark's shoulder. Cut to a close up of Martha as Jonathan calls her name but now he has both his hands on Martha's face.
Continuity mistake: Joseph, Kyla and Clark are at the Talon, in the scene after Joseph is bailed out of jail. Martha comes in and walks over to the three of them. The next shot has her stopped next to Clark, with no forward movement to indicate she is still walking to him. In the shot after that she is still walking up to Clark.
Continuity mistake: When Clark decides to stay home from school because he cannot control his heat vision, his father decides to have a talk with him. Jonathan pulls his son to face him and them places both his hands on Clark's shoulders. Cut to a different angle as Jonathan says: 'Clark, look at me ' but now we see his left hand on Clark's neck. Cut back to the previous angle and his hands are on Clark's shoulders again.
Continuity mistake: When Martha is in the kitchen and starts having a coughing fit from the toxin, she drops the pitcher of lemonade. The pitcher lands on its side and breaks, but in the next shot, the broken base is positioned upright, sitting level on the floor, the jagged broken edges waiting to impale Martha.
Continuity mistake: When Lex is talking to Lionel outside the building site at the end, Lex's sunglasses disappear while the camera is on Lionel and reappear when back on Lex. This happens after Lionel turns to face slightly behind Lex and continues throughout the rest of that exchange.
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.
Deliberate mistake: Clark's CPR form is terrible. When he performs emergency breaths on Lex, Lex's chest doesn't rise and fall, indicating that he's not actually breathing much air in. He doesn't bother to measure for the proper location for chest compressions, a very important step that is the difference between proper CPR and simply cracking ribs. As he performs compressions, he is not chanting the rhythm (one-and-two-and-three) and his elbows are bent. All of these were altered for dramatic reasons or the purpose of safety, but the sloppy technique probably would have killed Lex.
Plot hole: In the episode Onyx, Lex's alter ego holds him hostage in the wine cellar claiming that when they were kids, Lex accidentally got locked in down there. In the pilot episode, it is established that although Lionel had the castle shipped over from Scotland brick by brick and built, they never moved into it.