Continuity mistake: Jonathan reveals the kryptonite to Clark/Dawn and Clark starts to react to it. Because of the kryptonite Clark drops the tiara he took from Chloe and it hits the floor near Chloe's hand. Then, just before Dawn is forced out of Clark's body, the tiara has slid several feet away and is now close to the furnace. Clark turns his attention to Chloe, she is faking an injury at this point, but now the tiara has moved back to be near her hand.
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.
Continuity mistake: Jason accesses Lex's computer and Lex catches him. After a discussion on an email Jason found Lex says "Burying ladies in the backyard isn't exactly a hobby of mine, Jason." Lex then just stands there staring at Jason. During their stare down the camera jumps back behind Lex and then back to behind Jason. During these camera changes the lighting on the left side of Lex's face changes. When the camera is behind Jason, Lex's left side is dark. When the cameras is behind Lex, Lex's left side is lit up.
Continuity mistake: Lana looks over the edge of the crater and there is a fire right in front of her on the inside rim of the crater. When the shot changes and pans up to an overhead view of the crater and ship that fire is missing.
Continuity mistake: Clark had been wearing his cap and gown for a while. When he takes them off while coming off stage the blue shirt he has on underneath has fresh raindrops on it like he had only put the cap and gown on a few minutes before the shot.
Continuity mistake: The raindrops on Clark's shirt disappear and reappear between shots. Clark's shirt is dry when he turns to Chloe and asks "I'm not normal?" but before and after this his shirt has raindrops on it. This happens again a few moments later as Lois starts to talk about "panicking in times of crisis", Clark turns towards Lois and his shirt is dry.
Revealing mistake: As the helicopter that Lana is in dodges the falling meteors in mid-air, the camera shot focuses in on the cockpit. If you watch Lana's position as she first starts to appear she is semi-transparent and the frame of the window behind her is visible through her body.
Continuity mistake: Jason Teague arrives at the Kent farm. He fires a shot into the windshield of the Kent's truck. So we obviously know the gun is loaded. Later, inside the Kent's house, Jason still has Jonathan and Martha held hostage. After Jason mentions the symbols burned into the field Martha says she doesn't know what he is talking about. Jason gets upset and racks the shotgun but when he does no shotgun shell, used or unused, is ejected. Now Jason would have had to keep the gun loaded while moving Jonathan and Martha back to the house as he would have had no time to unload and reload his gun.
