Trivia: While Mr. Freeze is at Shaugnessy's, when Shaka smacks Dick across the room, he ends up flat on his back, and in the close-up when Dick raises his head, the buttons on his vest switch sides momentarily. Then the buttons revert back (noted in trivia because it's better when clicked through slowly). (00:24:25)
Trivia: Arthur has a copy of The Blue Boy by Thomas Gainsborough hanging on his wall. The same painting is appreciated by Joker in the 1989 Batman movie.
Trivia: When Kevin is in Buzz's bedroom, he finds in the box a picture of Buzz's girlfriend. This is actually a picture of the art director's son dressed up to look like a girl, because the director, Chris Columbus, thought it would be too harsh to make fun of a girl like that.
Trivia: Spoilers: There's a pretty subtle bit of foreshadowing in Gary's house. When he's seated and the group is playing Jenga, if you look behind Gary, there are two old-fashioned guns on the mantle. The way the shots of Gary are framed throughout the scene, both guns are pointed right at him several times. Later in the movie, Gary ends up being shot twice by two different guns - once by a gun loaded with blanks and once by a gun loaded with live ammunition.
Trivia: At the festival when the Green Goblin throws his grenades, before the shot of Parker, you see Stan Lee (creator of Spider-Man). He was supposed to pick up the little girl that he pushes to safety, but due to his age, after several takes he said if they wanted him to pick her up, they were going to be there all day. (01:04:10)
Trivia: The $100 bill in the closing credits has the serial number DOT00002018. Which stands for Den of Thieves 2018, the year it was released. (02:24:00)
Trivia: There are brief cameos at the start of the film by Peter Jackson as Bad Santa, who stabs Nicholas, and Garth Jennings as the Crackhead who holds hostages. Later, Cate Blanchett appears as Janine, who is hidden behind a surgical mask, and from whom Nicholas is estranged. And the film's director, Edgar Wright, is seen as the store employee pushing the cart when Nicholas walks towards the manager's office.
Trivia: On the "subway" train, the man holding the USA Today paper is Cameron Crowe, and the woman in the seat behind him on his left is Cameron Diaz. Because "Vanilla Sky" and "Minority Report" were so close in shooting, the two directors (Crowe and Spielberg) agreed to put themselves as cameos in each other's films. (00:46:10)
Trivia: The Christmas ball scene is symbolic: since it is a masquerade party all the guests are in disguise. The only guests who aren't wearing masks are Bruce Wayne and Selina Kyle. This implies that their real personalities are Batman and Catwoman respectively, and that their public persona is the real disguise.
Trivia: In the opening musical sequence when they jump out of the pool, the lady behind Austin can be seen laughing because her swim hat has fallen down.
Trivia: In the scene where Alex approaches the two girls at the record stand you can see the original score for 2001: A Space Odyssey, also directed by Stanley Kubrick.
Suggested correction: The album shown in the picture is NOT, as is commonly believed, the soundtrack of 2001, but rather a compilation of movie theme music that includes the main theme of 2001. However, the ACTUAL soundtrack of 2001 is still visible in the scene, just a little earlier: When Alex finishes flipping through a magazine and tosses it down on a counter, one of the records in that shot is the 2001 soundtrack.
Trivia: Director Martin Scorsese makes more then just a cameo in this film, he's the passenger that sits with Travis talking about how he's going to kill his wife for cheating on him with a black man. He's credited as "Man Watching Silhouette".
Trivia: Anthony Stewart Head (of "Buffy the Vampire Slayer" fame) makes a cameo as the man who congratulates Sweeney after his competition against Signor Pirelli. Head originally had a larger role, but his scenes were eventually cut out. (00:38:25)
Trivia: The corpse of Sid Shattuck, which Ryan Gosling discovers after his drunken roll down the hill, is played by an uncredited Robert Downey Jr., who'd previously starred in Shane Black's "Kiss Kiss Bang Bang", a film which played a large part in revitalising his career after drug and legal issues.