Revealing mistake: The Smallville Torch that Clark looks at online is the exact same one last seen by Lex two episodes ago in "Craving." This wouldn't be a problem, but Clark remarks that this Torch is "another scathing editorial," indicating that it is new, and Principal Kwan complains that parents have been calling all morning, which means that this issue of the Torch was published either this day or the day before. Prop department must have been saving money.
Revealing mistake: At the command center outside Martha is watching a monitor with the hostages on it and she asks "Where's Clark?". The next shot is one of Clark running down a hallway, inside the plant, using his super-speed. As he is running the red lights along the ceiling are revolving faster than they normally do and return to normal once Clark stops using super-speed.