When we first see the naked Oscar hanging from the gable on the roof of the house, he's about three feet from the window. Subsequently, in close-up he's much closer than that, and we can see Jeff reach right out and grab him, as he is much closer to the window now than before.
Jeff says he's a pharmacology student. His father Duncan asks him how things are going at Pepperdine. Per their own website, Pepperdine has no pharmacology program. He is using term "pharmacology student" as a euphemism for "drug dealer."
The Chrysler 300 that Norman and Derek are riding in is constantly changing headrests/seats between Cadillac and Chrysler, back and forth.
When we first see Jeff, he is playing the video game Uncharted. However, when he appears to lose the game, you can faintly hear the "game over" sound from Metal Gear Solid, a completely different video game series.
When we first see Norman driving his Chrysler, the steering wheel is upside-down despite the fact that he's driving straight.