During the opening scene, behind Jesse you can see the vice principal walk up behind her and reach out as he's about to put his hand on her shoulder, yet the very next shot of Lana, in the background you can see he's just exiting a room.
During the second part of the opening scene at around 3 minutes, U.S Marshal Ted Palmer (played by Michael Tomlinson) locks the slide of his Glock 17 to the rear while menacing the guy in the tub. This was likely inspired by handguns with visible hammers that can be cocked and de-cocked in a way that lends itself well to film. Until the slide is sent forward (using a lever on the side of the firearm), the Glock is not able to fire.
Lionel Luthor revamps Lex's office to make himself more comfortable, but the changes include the addition of 10 computer monitors and a red stock ticker, all of which are useless to the completely blind Lionel.