Jodie Foster was originally signed to play Michael Douglas's sibling in the film. However, Foster changed her mind and wanted to appear as Douglas's daughter instead. Douglas and director David Fincher were very opposed to this change so the part went to Sean Penn instead. Foster promptly sued PolyGram to the tune of $54.5 million - even though her Egg Pictures was one of the film's production companies. The matter was fortunately settled out of court. Douglas - who is a personal friend of Foster - said that it didn't seem right for him to play Foster's father, given that there is only 18 years age difference between the two. Ironically, Douglas HAS already played Foster's father - he did so in the Disney film Napoleon and Samantha (1972) at the start of both of their careers.
Among the tests that Nicholas is asked to take when he interviews at CRS is the MMPI. This is the Minnesota Multiphasic Personality Inventory which is one of the most commonly used personality tests in mental health. The test is used by trained professionals to assist in identifying personality structure and psychopathology.
Nicholas's "San Francisco" home was actually the historic Filoli Mansion, 25 miles south of San Francisco in Woodside, California. The plain gravel forecourt of the mansion was made to look more like a wrap-around driveway by the addition of the fountain, which was constructed of lightweight foam. The interior shots of the kitchen were made in the original time-worn kitchen, which is displayed on tours but no longer used. The kitchen's state of repair is not good, which partially accounts for the very dim lighting used in the kitchen scenes. The scenes in which the walls were defaced with graffiti was done by tacking up lightweight graffiti-painted foamcore boards over the wood paneling. All of the scenes at the mansion were completed in one day.
David Fincher claimed in an interview, in UK film magazine Empire, that there is a can of haggis in every scene of the movie. This was done as a joke, because "Haggis" is the nickname of cinematographer Harris Savides.
In searching for a perfect engine sound for Nicholas' 7 series BMW, one member of the sound editing team located in Sausalito, CA actually borrowed his high school friend's Dinan modified BMW 540 for half day.
"The Game" is essentially a modern retelling of Charles Dicken's "A Christmas Carol". Both tell the story of a rich lonely man who on a holiday (birthday or Christmas) view scenes representing the past present and future leading to him reevaluating his life and changing for the better.
Conrad's use of the pseudonym Seymour Butts and Nicholas' response of, "'Under the Bleachers' by Seymour Butts", is a reference to the joke series "A Book Never Written" featured in Boys' Life (the official magazine of the Boy Scouts of America).
Nicholas Van Orton celebrates his 48th birthday in the film, however on the film's US release (12 September 1997), Michael Douglas was actually only 13 days from his 53rd birthday - (born 25 September 1944).
Michael Douglas produced Face/off that very same year starring John Travolta and Nicolas Cage. Tommy Flanagan in this film also appeared in that film as well. Sean Penn worked with Travolta and Cage before.
Two actors from this film, Armin Mueller-Stahl and James Rebhorn, were involved with some adaptation of Reginald Rose's play "12 Angry Men". In fact, both played the exact same character, the Juror #4: Mueller-Stahl in 12 Angry Men (1997) while Rebhorn was part of the 2004 Broadway revival.
The scene in which Nicholas wakes up in a crypt in Mexico is an homage to the film Bring Me the Head of Alfredo Garcia (1974), in which protagonist Bennie is buried alive in a Mexican cemetery and must claw his way out of a shallow grave. Nicholas' kidnappers even re-dress him in the same suit that Bennie wears through the duration of that film.
In the final climactic scene, one of the paramedics is played by Spike Jonze, a fellow director of music videos prior to embarking on a feature film career. In the Spike Jonze-directed Being John Malkovich (1999), David Fincher has a cameo in the documentary section.
The film could had a possible alternate ending which could had seen Nicholas, after shooting Conrad, commits suicide for real and instead jumping through the glass roof and landing on a giant airbag in the ballroom. Nicolas jumps and hits the pavement hard below. Conrad, Christine and the party guests race outside and panic, realizing that their birthday hoax has gone wrong and that they have gone too far. Conrad produces the T-shirt that he bought as Nicholas's birthday gift "I was drugged and left for in Mexico - and all I got was this stupid T-shirt." and breaks down in tears and says "This was his birthday present."
An alternative ending could also be where Nicholas kills his brother Conrad in the roof, much similiar to the script of "the game" ,and jumps from the top of the building and falls through the glass, but instead of landing on a giant airbag, he lands on hard floor floor painted with a "X" sign. And so C.R.S. got rid of both brothers and took Nicholas's money. This also matches with the tagline of the movie : "The Game, You Just lost". He did indeed.