New this month Plot hole: In this episode, Pete comes across Clark's spaceship in a field, where it landed after the tornadoes hit the town during the last episode of Season 1. The Kents knew the spaceship was gone, and of course it was important that they attempt to get it back as soon as possible so it doesn't fall into the wrong hands. With Clark's speed and x-ray vision, he should have been able to find the ship after not too long of a search (especially since it was within a few hundreds yards of a road). It seems implausible that he would not have looked for it, given its importance.
Other mistake: Lois digs up Chloe's grave site to unearth her casket. It is obvious that the casket is not buried six feet deep. You would think, will all that is going on, that LuthorCorp would have at least buried the casket deeper to deter inquisitive eyes and maybe throw in a few scattered bones for good measure.
Visible crew/equipment: When Clark finds Lex in the Luthor mansion, they walk down the hall and into a new room. As they enter, as Lex is saying "So, hows the new ride?" if you look in the bottom left of the screen you can see a white tape marker on the floor, where Lex will walk over to subsequently.
Audio problem: Clark listens to his father and Earl talking in the hospital through the visitor window. The sound is the same volume and quality as when Earl was using the microphone, which he is not using now. Even if Clark used super-hearing to eavesdrop, it wouldn't sound the same as the microphone.
Revealing mistake: When Tina puts the necklace on Clark to disable him, he falls to the ground of his barn. As he is lying there, his collar is very dark, and his shoulder is lit up. Since the source of the green light is supposed to be the necklace, his collar should be the brightest lit.
Continuity mistake: When Lana shows Chloe the picture of her mother and Henry Small. We see that Chloe holds the picture on its bottom corners with both her hands. Cut to a close up of the picture but now she is holding it in the bottom middle of the picture. Cut back to the previous angle and she is holding it by the corners once again.