Smallville Season 4 Episode 14

When Clark and Lois are driving, the viewers can see in the front of the car the car brand (GMC), but when Lois and Clark stop driving, the logo that says "GMC" is gone (it's covered in black).

When Hercules is biting Jonathan's arm, you can clearly see he is wearing a protective arm pad under his jacket.

In the beginning, when Lois hits the dog, and stops, at first she has the car's lights off, and in the next shot they are on.

Martha was cooking John t-bone steaks? For a man with a bad heart and who has had a lot of ill health and surgery recently, he shouldn't been eating these (even though in the end he didn't get to).

If the Kryptonite liquid drug that spilled on the floor was affecting Clark, wouldn't the liquid be on Clark's jacket when Einstein is dragging him out of the truck? And if so, Clark wouldn't regain his strength until he took off his jacket.

When Clark gets into the back of the van the first time, he is several feet away from the kryptonite tubes but doesn't feel anything or seem to notice them. It's only after they get broken open that he starts getting affected, even though he's just as close. Which doesn't make sense unless they were lead-lined, which they clearly aren't.

When Clark gets into the back of the van the second time to rescue Krypto, he doesn't notice the kryptonite even though there's no indication it was cleaned up or disappeared or anything.

When Shelby breaks Hercules out of the burning van, he clearly misses the button with his nose, However, it still beeps and releases the cage door.

When Einstein presses the button to open the cage and Clark falls out, you can clearly see that, although there's a green glow, there are no Kryptonite puddles which would have caused the glow.

At the end of the episode, Shelby was clearly wet in the barn following his bath. Yet he is all dry, and even freshly brushed, when playing with Clark outside just moments later.