451 - The code, "1540" used to open the first locked door in BioShock 2 is a reference that has been used in several games made by previous employees of Looking Glass Studios since the creation of the System Shock game series, the predecessor of the BioShock games. In System Shock the first locked door could be opened with the code 451. In System Shock 2, there was a door that could be opened with the code 45100. In the game Deus Ex (which was made by Ion Storm, a company with several previous employees of Looking Glass Studios) 0451 was a code to open an armory. In BioShock, 0451 opens a locked closet in Twilight Fields Funeral Homes. In BioShock Infinite, 0451 is the code to unlock an elevator. The number itself comes from the title of a book by Ray Bradbury, "Fahrenheit 451."
Hitman - In Pauper's Drop, the Fontaine Clinic door code is 0047, which happens to be the code name for the protagonist in the video game series, Hitman. Also, the name of the person who recorded the Audio Diary pointing to the code is "Tobias Riefers"—an alteration of "Tobias Rieper," the name that Agent 47 gives as a pseudonym in the mission "Traditions of the Trade" from the original Hitman game.
System Shock - The achievement/trophy name "Look at you, Hacker" is a reference to a well-known (though unused) line by the main antagonist, SHODAN, in System Shock, BioShock's spiritual predecessor.
Unstable Teleport Plasmid - This defective Plasmid found in Fontaine Futuristics is a nod to the Teleport Plasmid which was cut from BioShock due to the many glitches it would have caused. It also briefly shows a Splicer being surprised by your appearance, a reference to Half-Life 2 in which a malfunctioning teleport will do the same thing, albeit with much larger consequences.
Thief - One of the possible names a hacked Security Bot can be assigned is "Garrett," the name of the protagonist from the game Thief. Also, female Splicers will occasionally say "You can't hide in the shadows for long" if they are alerted but cannot find you — guards in Thief sometimes say this exact line when searching for the player.
Detective Suspects - Scraps of paper on the wall in Detective Rock Flanagan'soffice in Pauper's Drop list the names of several BioShock 2 developers. On a scrap labeled "Insane": Collin Fogel, CJ Green, Karina Riesgo, and Brandon Pham. On the scrap labeled "Special": Rinaldo Tjan, Brandon Pham, and Rich Wilson. Viewing the complete texture file reveals the title as "Special Treatment" or "Treatment".
Gilbert Alexander - Gil Alexander's name was a tribute to Stephen Alexander, an FX artist at Irrational Games who was influential in the making of BioShock.
Handyman - A tonic acquired in the game assigns random names to any Security Bots that the player hacks. The player can control two hacked bots at the same time, creating several name combinations that are references to characters in the game, members of the game development team, or other real life people: "Rachel" & "Steven", "Andrew" & "Ryan", "Tommy" & "Rebecca", "Jordan" & "Thomas."
Penal Colony Inmates - Several names of inmates in Persephone are taken from members of the BioShock 2 development team (Mattson, Wilson, Thomas).
Steve Gaynor's girlfriend - Steve Gaynor, the level designer for Adonis Luxury Resort and Pauper's Drop, makes a reference to his girlfriend Rachel Jacks in the Audio Diary Fitness in Adonis Luxury Resort. In the sauna, there is an Audio Diary by "Rachelle Jacques." Rachelle has a husband named "Stephen" who sits around listening to radio serials while she swims laps at the Adonis. According to Gaynor, Rachel goes to the gym while he stays home and plays video games. A photo on a wall-mounted shotgun rack in the Fishbowl Diner is a picture of Rachel.
Doctor Who - The inspiration for Sofia Lamb's character was that of Fenella Woolgar's role as Agatha Christie in the tv-series Doctor Who.
Judas - Sofia Lamb compares Stanley Poole with Judas Iscariot, the disciple who betrayed Jesus, in her audio diary A Spy.
Louis the 15th - Eleanor Lamb breaks a tea service in the style of Louis XV of France, which can be heard in her audio diary Destructive Learning. Louis XV was one of the kings of France during the 18th century.
Nighthawks - Pauper's Drop's Fishbowl Diner was inspired by the painting Nighthawks, by the American artist Edward Hopper.
Revelations - The graffiti on the plaque directly across from the Vita-Chamber where Subject Delta first awakens in Adonis Luxury Resort reads "Fallen, fallen is Babylon." This is a reference to the Bible passage Revelation 18:2, "Fallen! Fallen is Babylon the Great! She has become a home for demons and a haunt for every evil spirit, a haunt for every unclean and detestable bird."
Schrödinger - A frozen cat in Imago Fine Arts is a reference to Schrödinger's cat; a thought experiment by the famous physicist Erwin Schrödinger, who postulated theories about quantum entanglement.
Tamara de Lempicka - Tamara de Lempicka was a Polish Art Deco painter active in the 1920-30, who's art style inspired several of the Art Deco paintings in BioShock 2, notably featured in the Journey to the Surface and Dionysus Park. The texture files for these particular paintings are labeled Lempy_01_diffuse.tga, "Lempy" being a reference to Lempicka.
The Wizard of Oz - BioShock 2 has a few references to the cult MGM 1939 film, The Wizard of Oz:
If Delta chooses to save the Little Sister in Ryan Amusements, Sinclair will say of him that "our tin man had a heart all along," an allusion to the Tin Woodsman, a caring character of the story who seeks an heart without realizing he doesn't need one.
Sinclair also comments in an audio diary that Andrew Ryan "reckoned the free market was some kinda holy spirit gonna lead us all over the rainbow," a possible reference to Over the Rainbow, the most popular song from the film, reflecting the main character's dream of finding a place out of all trouble.
A concept art for a heaven-like outside appearance of Persephone (similar in shape to the definitive rending) had Persephone look like a green crystalline and transparent structure, which share similarities to the Emerald City of Oz. Coincidentally, the protagonists of BioShock 2 follow a single road to it (the Atlantic Express line) just as Dorothy and her friends walk along the Yellow Brick Road to the Emerald City. In both stories, the destination at the end of the road is the place where their wish are granted.
The song is heard in the Puppet Workshop of Ryan Amusements. The technician for the park's animatronics, Carlson Fiddle is quoted in the novel as being inspired by the Westinghouse Electric Corporation exhibit in the 1939 Fair which featured "Elektro the Moto-Man", a 7-ft tall robot that could talk, walk, smoke cigarettes, and distinguish colors with his dog "Sparko" who could bark, sit, and beg.
Bessie Smith - The character of Grace Holloway was partially inspired by the life of a 1930s blues singer named Bessie Smith.
Pavlov's Dogs - Suresh Sheti uses the term "Pavlo's pets" to describe his audience in his audio diary Intellectual Stimulation. This referes to Ivan Pavlov's famous experiment with classical conditioning on his dogs.
Playboy - Oscar Calraca's nickname, The Playboy, is an obvious reference to the Playboy magazine.
Rita Hayworth - The appearance of the playable character: Mlle Blanche de Glace, was modeled after a picture of the famous actress Rita Hayworth.
Shirley Temple - Louie McGraff refers to the famous child star of the 1930-60 when he picks up the Little Sister, by saying "Alright Shirley, come 'ere!"
The Kraken - The mapPoint Prometheus features a Kraken exhibit with a large statue of the mythological octopus Kraken. The exhibit was inspired by the movie 20,000 Leagues Under the Sea, which the multiplayer art director Mat Tremblay, saw as a child.
Minerva - Minerva, the namesake of the DLC and the first level, is the Roman goddess of wisdom. Her symbol is an owl, which is seen in numerous places throughout the DLC.
Hedy Lamarr - The name of the Minerva's Den exclusive Splicer model Heady, is a reference to actress Hedy Lamarr.
Named cats - Each level in the Minerva's Den DLC features a single named cat corpse.
Minerva's Den - Babbage: Named for Charles Babbage, the man credited with inventing the first mechanical computer.
Operations - Lovelace: Named after Ada Lovelace, a woman credited with having written the first algorithm intended to be processed by a machine.
The Thinker - Turing: Named after Alan Turing, who conceptualized the "Turing Machine."
Named slugs - Nine sea slugs found in jars are named after main developers of the DLC, including Steve Gaynor, Devin St. Clair, Jeff Fisher, Scott LaGrasta, Mario DiPesa, Rinaldo Tjan, Will Armstrong, Collin Fogel, and Brandon Pham.
The Thinker - The name of the Rapture Operational Data Interpreter Network is inspired by the famous statue of the same name, sculpted by Auguste Rodin. The acronym of the computer's name is R.O.D.I.N.- the last name of the sculptor. A version of The Thinker sculpture can be seen in the lobby of Minerva's Den.
Clock - Lead designer Steve Gaynor has stated that the inspiration for the clock room in the Executive Wing came from the 1994 Coen Brothers film, The Hudsucker Proxy. During the film, the clock takes up an entire wall in the company director's office. During a pivotal plot point, the clock is also stopped near midnight.
↑Deco Devolution: The Art of BioShock 2, Environments section, pg 82: "We really started with a tenement district and diner. Early on Jordan wanted to have some sort of diner. He was thinking of Edward Hopper's painting and the idea of a lonely character hanging out in diners Everything changed but the diner. Early on in development we realized we had so much content we had to break it into two maps so part of it went into the Pauper's Drop map and the other went into the Siren Alley map." - Alex Munn
↑Deco Devolution: The Art of BioShock 2, Environments section, pg 117: "The Kraken is probably one of my favorite assets in the whole game. This guy was one of those things that came to my memory from watching 20,00 Leagues Under the Sea as a kid and being freaked out by the huge Kraken that takes a sub. It seemed perfect for this map. It was a real challenge, though. To model this and texture it and get it in place was a couple weeks worth of work. It turned out really well. I would say that, even though it's not in the actual center of the map, it's definitely one of the centerpieces of the map." - Mat Tremblay