When Lex is about to hit Clark with his car, Clark alternates between facing the car and facing the bridge.
When Clark starts to argue with his dad about the truck Lex gave him, he throws his backpack and jacket down on the stairs in the barn. He goes over to the woodchipper and shoves his hand in it, the camera pans to his dad and you can clearly see the stairs behind him, the backpack and jacket are no longer there. Also when Clark storms up the stairs after he's done arguing with his dad, the backpack and jacket are no longer there.
After the meteor shower, the bit of hair that Mr. Luthor finds in the cornfield changes in his hands from stretched straight to curled.
The hole in the guard rail changes size and shape between the shot of Lex driving off it and another looking up at it from below.
Closeups and wide shots on the Wall of Weird show different things next to each other. Watch the objects surrounding the finger article and the Wall of Fire article in the wide shot on Chloe, then look again at the closeups.
Ther license plate on Lex's car is a Metropolis license plate. Unless Metropolis became the 51st state, the plate should have said Kansas.
Lana rides up to the cemetery on a horse but later walks home with Clark, leaving the horse behind. However, the cut is actually directly from the cemetery to a scene showing Clark and Lana walking towards Lana's house from the stables. Obviously they walked to the stables, with the horse, and left it there.
The Porsche that strikes Clark has no sign of impact when it goes over the side of the bridge. Clark is meant to be a "Man of Steel" and definitely would have caused visible damage to the Porsche as it flies over the edge.
When Jonathan lectures Clark about the danger of accepting gifts from Luthers, the key he twirls is a GM truck key, not a Ford truck key.
When the meteor hits the road in front of Jonathan and Martha's truck, Jonathan slams on the brake, trying to stop the truck, but then the shot changes to a different camera that shows the truck casually driving into the smoke.
Before Lex hits Clark, it shows the truck coming off the bridge, and Lex's car close to coming on the bridge at 60 mph. Then it shows a shot of Lex inside the car, and through the window, it looks like he is driving in the middle of a field instead of on the bridge.
When Whitney pushes Clark to the ground before talking him to be the scarecrow, you can see the elbow pads Tom Welling is wearing.
When Lex spins up to Luthor Corp in his car, as the camera pans over the car to follow him, the cameraman is reflected in the window as he pans over.
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, how's 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.
A spaceship would never come to Earth together with meteorites, if they all started journey together, as a spaceship has a propulsion and travels faster than parts of planet that exploded and just floated across universe. However, it has been established in the comics that Kal-El's ship created a wormhole which remained open and the meteorites were drawn in after it, which explains why there is so much Kryptonite on Earth.
In the first scene at school, while discussing the strange goings-on in Smallville since the meteor shower, Pete uses an analogy that "Chloe's weirdar is on DEFCON 5." DEFCON 5 is the lowest level of alert readiness, and essentially indicates that everything is fine; it's DEFCON 1 that is the most severe.
It is evident that Clark already has super speed, therefore when Lex's car swerves toward him on the bridge he would have easily been able to sidestep it rather than be hit by it and knocked into the river.