Continuity mistake: The meteors are shown traveling together in space at the beginning, but the smoke trail from the first meteorite runs perpendicular to the flight of the next one. They should be falling along roughly the same flight corridor, as all the other meteorites do.
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.