Visible crew/equipment: As Jonathan is being attacked by Hercules you can see that Jonathan, or his stunt double, has on a arm cuff that is used for protection of attack dogs.

Continuity: When Chloe pulls up to Clark's house there are patches of snow everywhere. While Clark hears the dog crash through the fence the fields are visible through the screen door and there is no snow on the ground at all.

Revealing: As Krypto presses the button to open Hercules' cage you can hear the button beep as if it has been pressed but the green light is still on. Earlier the beep which means the button worked also turns off the green light.

Continuity: Clark goes to see Lex about the dog. Lex, who was about to start a game of pool, breaks a fresh rack. Lex then goes to make his second shot from near the side pocket and as he does you can see there are two striped balls near the rail close to Lex's cue stick. Just after he takes his shot those balls are gone even though those balls had not been hit.

Factual error: Clark huddles over Krypto to protect him from the blast of the exploding van. He does not cover Krypto's head before the blast of fire hits them yet Krypto shows no sign of damage. At the very least the fire should have singed his fur.

Revealing: When Clark throws the two villains against the brick wall at the end, it very flexes as though made of foam rather than brick.

Continuity: Before Clark throws the two bad guys against the side of the barn there is no snow falling at this point. When the shot switches to Krypto saving Hercules you can see that now it is snowing rather heavily. This is far too fast to happen naturally.

Continuity: The guide that was with Lana gets killed by soldiers. When the guide is shot you can hear that the weapon has a silencer on it. About a second later we see this still smoking gun has no silencer on it.

Other: Clark is told by Jor-El, his Kryptonian father, just how important the 3 stones/crystals are. So later it makes no sense for Clark to stop just after he takes the stone from Isabel/Lana. Clark could just as easily kept running with the stone and hidden it before Isabel/Lana even realizes he took it.

Plot hole: In episode 4-16: "Lucy," there is no reason for the criminals to be chasing Lucy on the ski slopes at the beginning of the episode. We learn later that she's been working with them all along; she calls Lois during the chase, and the call is part of Lucy's plan with the criminals. Lucy being chased by the criminals would make sense given the story she gives Clark during the next part of the episode, but it doesn't make sense for what we ultimately learn is the truth. And nobody from Smallville is anywhere near the ski chase, so it also doesn't make sense as any kind of a ruse.

Continuity: As Clark first gets to the bridge at Cherry Hill, the shadows establish the time as either early morning or early evening since the shadows are long. In several shots during this scene the sun suddenly jumps to around noon as the bridge shadow goes from sticking out far to one side to being almost directly under the bridge and the shadow of the semi shortens when Clark is making his super jump.

Factual error: As Clark is chasing after the semi-truck with Lois and Lucy in the trailer you can see the Rocky Mountains in the background. Kansas doesn't have mountains. However, Vancouver, where the show is actually shot is home to part of the Canadian Rockies.

Visible crew/equipment: Just after Becker starts to chase Lucy there is a shot looking up the hill towards the lodge where she started skiing from. To Lucy's left you can see a fresh pair of ski tracks being made by whatever the camera is on. You can tell these are fresh tracks because there is fresh snow being kicked in the air because of them.

Continuity: In the barn loft evil Lex has a kryptonite ring in a lead box. When the camera is in front of Lex he is holding the box so that the lid is pointed towards his thumb. When the camera is behind Lex the box is turned so that the lid is pointed towards the end of his fingers.

Continuity: As the computer says "Subject seeds exposed to radiation" there is a camera shot showing the temperature monitor in the lower right of the shot. In that shot the readout shows the temperature reading is close to 100% of maximum. Then, in the next shot as the scientist says ".absorption level: as expected" the temperature monitor is now close to 90% as we see it climb up to the 98% they were trying for.

Continuity: When Bad Lex is beating up Good Lex in the cellar right before their bodies are joined again, he repeatedly hits him on the right side of his face. However, when the two are finally fused back together, there is a bruising on the left side of Lex's face.

Plot hole: Clark is possessed by Dawn. Jonathan shows up and he has a chunk of kryptonite. Jonathan hides the kryptonite behind his back and Clark's body does not feel it until Jonathan takes the kryptonite out from behind his back. What, is Jonathon made of lead or something?

Audio problem: As the band is playing right before Clark and Lois enter the prom, the drums are not synced with the music.

Continuity: As Clark/Dawn goes to hit Chloe, at first the camera is behind Clark and he swings as if he is going to slap her face. The next shot, as the camera is to their side, Clark's swing changes so that he shoves her across the room.

Revealing: 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.