Other mistake: When Somerset goes back to the man's house alone, he cuts a sticker on the door with his switch-blade to get in. The first error is the sticker is on the inside and it says "Keep Out." The best part about it is the door opens inward. How did they put the sticker on the inside and then exit?
Continuity mistake: When they are in the car with heavy rain, you can see the pedestrians are NOT using umbrellas or wearing raincoats. Its also raining far harder on the left of the car than the right. In addition, Somerset is turning the wheel to the right, and yet theyre driving in a straight line.
Trivia: Kevin Spacey made sure that it was in his contract that his name would not appear in any press releases or reviews, that his photo would never appear in any of the above, he was not to be mentioned in interviews nor was his name to be anywhere in the opening credits. He cites his reason as being that The Usual Suspects and Outbreak were both opening earlier that same year and figured that people would start to recognize his name. And he also figured that if people saw his name in connection with the movie and he didn't appear for the first 2/3 of the movie they would know that he was playing the killer, thus ruining the element of shock and surprise that the moment in the movie has built up to. To compensate, Spacey is listed first in the ending credits.
David Mills: I've been trying to figure something in my head, and maybe you can help me out, yeah? When a person is insane, as you are, do you know that you're insane? Maybe you're just sitting around, reading "Guns and Ammo", masturbating in your own feces, do you just stop and go, "Wow! It is amazing how fucking crazy I really am!"? Yeah. Do you guys do that?
Question: I'm confused by how Victor (the Sloth victim) managed to "survive" an entire year of being tied to his own bed. Even if he had an IV keeping him alive, surely he would have died after a few months, even weeks? Also, how did no one notice him missing when he was trapped in a populated apartment? Surely someone would have noticed his absence; he was an infamous drug-dealer after all.