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.
Continuity mistake: Martha asks Clark to come out after he gets glasses. In the shot showing all three of them, Clark comes into view on the left side of the screen and is turned toward his parents. The very next shot shows he is just walking through the door of the optometrist and turned away from his parents as he closes the door.
Plot hole: In order for Clark to push Jason out of the way of the already fired shotgun blast Clark would have to be moving much faster than the shot. Hitting Jason at this speed would have caused Jason some serious injuries. When Jason is with Lana at the Talon he has no damage from the shove.
Factual error: Perry uses a simple black rope to tie himself to the railing by his ankle. This is not a bungee cord of any kind. He falls and is stopped, jerked to a stop actually, with both his weight and the weight of Clark pulling on his ankle. This would cause a very serious sprain if not an actual broken ankle yet Perry shows no signs of being injured when he and Clark walk to the bus.
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: Lex's aide is shot in the back as he makes a run for the door. When he goes down he slides head first almost all the way to the door. A few moments later, just as Flynn shoots out the security camera, in the security monitor image Lex's aide is now in a different position.