Jacob's line "You had sex with my grandpa, you dirty anchor baby!" was improvised by Jaeden Martell, but it was originally lost in the scene since multiple characters were talking and yelling. Michael Shannon noticed this and approached Rian Johnson, telling him that Martell had a killer line, so they made sure to go back and capture it.

It was Don Johnson's idea for his character to hand his empty plate to Marta as if she was the maid during the immigration conversation.

Rian Johnson said that Michael Shannon was by far the funniest person on set, and came up with a lot of his character's funny lines and physical moments, such as his triumphant arm-raise during the "eat shit" scene, and his retort: "I am not eating one iota of shit!"

When Ransom tells his family at the will reading to "eat shit," he was originally supposed to tell them "fuck you." Rian Johnson decided to remove most of the "F" bombs in the script to secure a PG-13 rating and keep it more like the mystery films he used to watch with his family growing up. Chris Evans was the one who suggested substituting "eat shit."

Despite playing his mother in the film, K Callan is six years and 27 days younger than Christopher Plummer. Plummer was born on 13 December 1929 and Callan was born on 9 January 1936.

Several characters refer to a fictional Hallmark movie starring Danica McKellar titled "Deadly by Surprise." Though McKellar was not asked if her name could be used, she was delighted that it was included, and she shared her love for this film on Instagram. She later sent director Rian Johnson a knife with the words "Deadly by Surprise" engraved on it.

Rian Johnson contemplated cutting Blanc's doughnut speech, but Craig convinced him that it was good. Watching the actor deliver it sold him on keeping the entire thing.

In the commentary, director Rian Johnson described Chris Evans' entrance when the barking dogs surround him at the will reading as some of the best acting he's seen, because "dogs love Chris Evans, and Chris Evans loves dogs."

Some of the interiors for the Thrombey Mansion were filmed at Ames Mansion in Easton, Massachusetts. The exterior of the house was a Gothic revival mansion built in the 1890s. It is located outside Boston but the exact location contractually cannot be revealed by the production.

Several artworks and window designs in the mansion feature the motif "memento mori," depicting scenes of everyday life populated by skeletons or skulls. The motif, which roughly translates to "remember you are mortal," was popular in the Victorian times and used to remind individuals that death comes for all people, whether rich or poor.

M. Emmet Walsh replaced Ricky Jay, who died during production on November 24, 2018. A black & white photo of Jay is visible for a few seconds just before Walsh first appears on camera, at (55:06).

Rian Johnson mentioned to costume designer Jenny Eagan that he thought Ransom would have beautiful, expensive clothes that he didn't take care of. Eagan ran with this, wearing holes into the sleeves his now-iconic sweaters and even distressing the heels on the loafers he wears throughout the movie.

Though a sequel Knives Out 2 (2022) was announced, the only relation it has to this film is the character Benoit Blanc (portrayed by Daniel Craig) who is simply working on his next mystery.

The portrait of Harlan Thrombey was digitally added in post production.

The painting of Harlan wasn't finished until after filming wrapped, so every scene showing it is an effects shot.

"I had written into the script that Blanc speaks with a subtle Southern accent," says Rian Johnson, and after they all finish laughing he explains that Daniel Craig researched accents and became attached to historian Shelby Foote's cadence and drawl. "So it's kind of that, it's a little Foghorn Leghorn, and it's also a little Harlan Pepper which is Christopher Guest's character in Best in Show (2000), which is funny because Christopher Guest is Jamie Lee Curtis' husband." Johnson added.

Both the title "Knives Out" and the working title "Morning Bell" are tracks from the album "Amnesiac" (2001) by the English rock band Radiohead.

The coffee mug that reads "My House, My Rules, My Coffee" was manufactured for the film. Replicas of the mug are now available for purchase.

Several Thrombeys tell Marta that they wanted to invite her to Harlan's funeral but they were "outvoted." The first time it happened, it sounds sincere and apologetic, but since it happened repeatedly and verbatim, it's a hint that the family considers Marta an outsider and are completely willing to turn on her.

Daniel Craig and Ana de Armas would later work together again in the 25th James Bond No Time to Die (2021). This is due to Craig choosing Armas for her role in the latter film due to the chemistry of them being able to work together during this film.

The opening shot required the two dogs to run from one trainer to another, but they initially had trouble getting them close to the camera. They ultimately had to build a little ramp so the dogs wouldn't slide directly under the camera.

The ransom email is sent using Proton Mail, a real secure and encrypted emailing service that is untraceable.

The coin Benoit Blanc flips is a 1901 US Morgan silver dollar. Since they were made of 90% silver, the government melted millions during WWI to help fund the war effort. Some are very hard to find, and depending on condition, they can fetch thousands of dollars.

All of the clocks and phones have accurate timing. In an interview, director Rian Johnson said: "Anytime a clock or a phone is in set, somebody has paid very close attention to the time and has asked me what time it's supposed to be in the actual scene."

At least two character names appear to be homages to "Who Killed Harlowe Thrombey?", an early entry in the popular "Choose Your Own Adventure" children's book series of the 1970s and 80s: The film's deceased patriarch, Harlan Thrombey, and elderly groundskeeper Proofroc (an inept detective named Prufrock is a secondary character in the book). The book, like the film, centers around the death of a wealthy man whose extended family are all potential suspects in his demise.

Daniel Craig sings the classic song "Losing My Mind" whilst waiting in the car. Daniel is a massive Liza Minnelli fan and insisted on using her version of this song from her collaboration with The Pet Shop Boys.

While shooting the interrogation scene with Linda, special lighting rigs were used that looked like windows so that the reflection in Jamie Lee Curtis' glasses would look like natural light filtering into the room.

Patton Oswalt contacted Rian Johnson after the film opened to ask if the needle drop of Gordon Lightfoot's "Sundown" at (1:21:47) was an intentional reference. Apparently, the song is (possibly) about a groupie Lightfoot had experience with named Cathy Evelyn Smith who's best known for being the one who gave John Belushi a fatal injection of heroin and cocaine in 1982. "And Patton, who is brilliant in his thinking in terms of 3D chess is like 'was that a crazy reference to Marta?'"

The beats with Benoit Blanc playing a piano key periodically were originally written with him sitting behind Lt. Elliott's chair and tapping it with his foot. Once they were on location, though, Rian Johnson realized that the geography of the room afforded him the better option of the piano.

Rian Johnson acknowledges that, despite numerous edits and attempts to shave it down, the script's opening interrogation sequence (complete with flashbacks edited in) was "always a really tough read." He would have people read it and adds that "I never didn't get the note that 'boy those first thirty pages are rough, and then it kicks into gear.'"

It was Toni Collette who picked the Roxy Music song, More Than This, that her character Joni Thrombey dances to early on.

At one point, Benoit Blanc references 'Gravity's Rainbow', the sprawling 1973 novel by Thomas Pynchon that won the National Book Award and was nominated for the Pulitzer but offended the Pulitzer Advisory Board because some members found it "unreadable," "turgid," "overwritten," and even "obscene," so no Pulitzer was awarded that year. Since Pynchon refused to turn up in person for the National Book Award ceremony, Viking Press sent a comedian to accept the prize in his place, and a streaker crossed the stage in the middle of the ceremony. Benoit adds that nobody reads the book, but he says he likes the title, which refers to the arc of German V-2 rockets during the Second World War, and the detective compares that to the arc of a murder mystery. Benoit refers to arc later in the story, as well.

Chris Evans got his dog, Dodger, a sweater that looks just like the one he wore in the film. Evans wore a white cable knit sweater in the movie and it quickly became an internet sensation.

A parenteral therapy of 100 mg of ketorolac given to a 85-years-old man for weeks, as Harlan takes in this movie, would be completely off-label and have a significant risk of kidney failure.

The film was shot on digital. In order to replicate the look of film, cinematographer Steve Yedlin wrote a script to create the halation glowing effect of film seen around bright light sources.

The board game that Harlan Thrombey (Christopher Plummer) and Marta Cabrera (Ana de Armas) are playing is called Go. Go is an abstract strategy board game for two players in which the aim is to surround more territory than the opponent. The game was invented in China more than 2,500 years ago.

The song Benoit Blanc sings while waiting in the car is "Losing My Mind" from the Stephen Sondheim musical "Follies". Oddly, the show, originally entitled "The Girls Upstairs", was conceived by Sondheim and playwright James Goldman as a murder mystery.

Jacob Thrombey (Jaeden Martell), the preppy grandson in the film who's always on his phone, was a character influenced by those that voiced their criticisms online over writer/director Rian Johnson's previous film, Star Wars: Episode VIII - The Last Jedi (2017), who he continues to characterize as "trolls" and "manbabies."

Rian Johnson wonders if anyone notices that Meg Thrombey Katherine Langford is wearing a black t-shirt that features a diagram of lady bits from around 10:29 to 10:38 minutes. "That might have been how we kept our PG-13" adds Noah Segan who was cast as Trooper Wagner.

Rian Johnson was asked about the moment in the movie where Joni Thrombey mentions she'd first heard about Benoit Blanc in a New Yorker article. In the piece, the investigator reportedly solved a case involving a tennis champion. "That's a very sly reference to one of my favourite movies, which is the 1970s version of Sleuth (1972)," Johnson explained: "In the beginning, the character of Andrew, who's played by Laurence Olivier, is a mystery writer dictating into a tape recorder the ending of his current novel, 'Death By Double-Fault', which describes how a body was discovered in a tennis court."

Rian Johnson has described Daniel Craig's character Benoit Blanc as an "American Poirot." Craig himself is British, although a naturalized American. This is oddly in keeping with Poirot, who is Belgian but is traditionally portrayed by an Englishman (Albert Finney, David Suchet, Peter Ustinov, etc.) or Northern Irishman (Kenneth Branagh). Benoit Blanc is also a plausibly Belgian name.

The Man Who Would Be King (1975) is one of Rian Johnson's favorite movies, so between takes he would try to get Christopher Plummer to talk about working with the legendary John Huston.

Rian Johnson's first time producing one of his movies.

In the scene where the actor approaches the house and the dogs bark at him from behind the fence, trainers walked the dogs to the set on the leash. Then the trainers placed two balls attached to rope and placed them in the actor's jacket pocket as rehearsed. The actor then walked to the car in the driveway. Trainers stood a few feet from the actor with the dogs on leashes. The actor lifted the balls and showed the dogs he had them. The dogs reacted by barking and pulling on their leashes.

Once the will has been read, Marta leaves and the family follow her. As they start to surround her, the camera goes from steadycam to handheld to show how overwhelmed she is, until she gets back in her car where it switches back to a steadycam as she feels safe.

The most impressive digital trickery is the shot at (17:21). It's a simple insert of a family photo on a shelf showing Richard Drysdale, his wife Linda, and their son Ransom. It was added to ensure audiences could put a face to a name, as characters were talking about Ransom before we'd actually met him. It was accomplished by shooting the framed photo in front of a green screen and then comping in one of the wide shots of the room slightly blurred as its background behind it.

The Thrombeys are named after 1970s rock stars; Richard and Linda are Richard Thompson and Linda Thompson, Joni is Joni Mitchell, Neil is Neil Young, and Walt and Donna are Walter Becker and Donald Fagen of Steely Dan. Except Ransom, who was named after a character from C.S. Lewis' Space Trilogy.

They recorded the commentary one week after it opened in theaters, and Rian Johnson's thrilled that Chris Evans' white sweater has entered the public consciousness.

The film's key greensman, Butch McCarthy, came up with The Menagerie Tragedy Trilogy on the day of filming after Rian Johnson asked the cast and crew for suggestions.

Every time Benoit Blanc hits the piano key, it's a cue to the Detective to ask them about the time they arrived at the party, in order to find out if they had any motives.

The dubbed program which Marta's mother watches is Murder, She Wrote: Who Threw the Barbitals in Mrs. Fletcher's Chowder? (1988), about a dinner party with homicidal results.

The early scenes show several of Harlan Thrombey's books. Two covers, shown framed side by side on a table, are "This Little Piggie" and "The Needle Game" which presage the motive and method of the murder plot. Other books include "The Wrong Tree", "Nick of Time", "The Badger", "The Keeper", "Ultimatum ", and "Homunculus", all of which relate to plot elements or characters. There is also "A Drop in the Bucket", which foreshadow's Marta's reaction when she lies.

The restaurant Marta and Ransom go to was called The Flat Penny and was located in Berlin, Massachusetts. It was not long after the shooting of the scene renamed to On the Trax and then closed down due to the illicit activities of the current owner.

The three television monitors in the security room are old monitors from Tandy / Radio Shack TRS-80 Model 1 computers.

Rian Johnson was happy to get a Stephen Sondheim reference in via Blanc's singing a song from "Follies" in the car. Legendary musical theater composer is a creator of puzzles (for New York magazine), and a fan of mysteries, having written two that were produced: The Last of Sheila (1973), co-written with Anthony Perkins and comedic mystery play "Getting Away With Murder", co-written with George Furth. The character in Sleuth that Laurence Olivier plays is based on Stephen Sondheim."

Marta's mother watches Murder, She Wrote: Who Threw the Barbitals in Mrs. Fletcher's Chowder? (1988), dubbed into Spanish. The dubbing for Angela Lansbury was done by esteemed television, film, and voice-over veteran Beatriz Aguirre, who died roughly two months prior to the film's release.

Rian Johnson met Noah Segan (Trooper Wagner) on their first film, Brick (2005), and they've remained friends and co-workers. "I finally wrote you a role that gets to the soul of Noah Segan."

Reunites Frank Oz and Jamie Lee Curtis, 36 years after they appeared in Trading Places (1983).

Marta drives by a car that has a "Keep calm and Bergeron" bumper sticker, referring to long-time Boston Bruin hockey player Patrice Bergeron.

The sailor figure at the foot of Harlan's staircase is similar to Jolly Jack Tarr the Jovial Sailor in mystery writer Andrew Wyke's home in Sleuth (1972).

The film secured US $40 million in funding at the Toronto International Film Festival (TIFF) in September 2018.

Daniel Craig and Ana de Armas reunite in No Time to Die (2021).

This is Rian Johnson's second movie shot partially digitally. Johnson's Director of Photography, Steve Yedlin, revealed in a tech demo that Star Wars: Episode VIII - The Last Jedi (2017) was also shot half on film and half on digital.

In January 2019, Rian Johnson tweeted a series of photos of the posters that he had hanging in the studio as he edited Knives Out to serve as inspiration for cutting the movie. These were posters for: Agatha Christie's Evil Under the Sun (1982) (1982; starring Peter Ustinov, Diana Rigg, and Maggie Smith); Murder by Death (1976) (1976; starring Peter Falk, Alec Guinness, Elsa Lanchester, David Niven, and Peter Sellers); Agatha Christie's Death on the Nile (1978) (starring Peter Ustinov, Bette Davis, Mia Farrow, and Angela Lansbury); The Last of Sheila (1973) (1973; starring Dyan Cannon, James Mason, and Raquel Welch); Deathtrap (1982) (starring Michael Caine, Christopher Reeve, and Dyan Cannon); Clue (1985) (starring Eileen Brennan, Tim Curry, Madeline Kahn, and Martin Mull); Gosford Park (2001) (starring Maggie Smith, Ryan Phillippe, Michael Gambon, and Kristin Scott Thomas); Agatha Christie's The Mirror Crack'd (1980) (starring Elizabeth Taylor, Angela Lansbury, Tony Curtis, Rock Hudson, and Kim Novak); the London production of the stage musical Something's Afoot (1977; starring Sally Smith); Agatha Christie's Murder on the Orient Express (1974) (starring Albert Finney, Lauren Bacall, and Ingrid Bergman); The Private Eyes (1980) (Tim Conway and Don Knotts); and Pokémon Detective Pikachu (2019) (starring Ryan Reynolds, Justice Smith, and Kathryn Newton). All of these are murder mysteries and/or detective stories, though some are satires of the genre. The screenplay for The Last of Sheila (1973) was co-written (with Anthony Perkins) by Broadway composer Stephen Sondheim, who also wrote "Losing My Mind," the song that Benoit Blanc sings some of in a scene in this movie. The Last of Sheila was Sondheim's only movie script.

The BMW that Ransom drives is a 1972 BMW 3.0 CSI. The model is referred to as an e9 by BMW and BMW enthusiasts.

One of three movies released theatrically in 2019 where, despite not being musicals, characters sing a song from a Stephen Sondheim musical. In Marriage Story (2019), the character played by Adam Driver sings "Being Alive," and the character played by Scarlett Johansson sings "You Could Drive a Person Crazy," both from Stephen Sondheim's 1970 musical Company. In Knives Out, the character played by Daniel Craig sings part of "Losing My Mind" from Sondheim's 1971 musical "Follies." Joker (2019), the bullies that attack Arthur in the subway sing "Send in The Clowns," from "A Little Night Music."

Throughout the film, the family has two pet dogs, who are seen performing such mild action as sitting/standing/lying, being held or petted, and walking/running on or off leash. For all of these scenes, trainers used hand signals and verbal commands to cue the mild action, which the trained dogs were accustomed to performing. The barking/growling was also a trained behavior.

The cast includes one Oscar winner: Christopher Plummer; and three Oscar nominees: Michael Shannon, Toni Collette, and LaKeith Stanfield.

According to Dr. Jackson Vane of Hi Everybody! A Bad Medicine Podcast (2019). Knives Out is "140% medically accurate." This means the film is considered 40% more medically sound than The Human Centipede (First Sequence) (2009), which marketed itself as "100% medically accurate" and is used as a baseline for comparison.

Although it was never explicitly mentioned, the political talk on Harlan's birthday party was about President Donald Trump's continuing of President Barack Obama's policy on illegal immigrants. Hints included mentioning "children in cages" and "red cap", indicating the "Make America Great Again" red cap featured prominently in Trump presidential campaigns.

Benoit Blanc almost speaks the film's title when he says "When people get desperate, the knives come out."

Thomas Pynchon's 'Gravity's Rainbow' is the first book that Rian Johnson ever gave Noah Segan who has not read it yet.

At one point Chris Evans's character refers to Daniel Craig's character as "CSI: KFC." Similarly, in Craig's film Logan Lucky (2017), a newscaster refers to the group of thieves as "Ocean's 7-11."

The blue arrow from Rian Johnson's Brick (2005) appears during the car chase.

Joni mentions she's not on Twitter anymore. In a deleted scene, it's confirmed that her company is bankrupt due to negative feedback so Joni shut down her Twitter account to stop angry customers hounding her.

The second movie where Michael Shannon plays Jaeden Martell's father, the first being Midnight Special (2016).

This is Daniel Craig and Christopher Plummer's second collaboration after The Girl with the Dragon Tattoo (2011), in which Craig played an investigative reporter and Plummer the old patriarch of a wealthy family.

This is the second consecutive film by Rian Johnson to feature Frank Oz, following Star Wars: Episode VIII - The Last Jedi (2017).

Marta Cabrera's apartment was filmed in a building once frequented by a young James 'Whitey' Bulger.

Both Ana de Armas and M. Emmet Walsh have appeared in the Blade Runner franchise, albeit 35 years apart. M. Emmet Walsh was Captain Bryant in the original Blade Runner (1982) and Armas was Joi in the sequel Blade Runner 2049 (2017).

This is Rian Johnson's first mystery movie since Brick (2005).

When Benoit Blanc is being introduced to the Thrombey family where it is referenced that he famously solved a case prior involving a tennis champ. We never get more detail than that, but Rian Johnson has revealed that backstory pays homage to Sleuth (1972). He said: "Yeah, a bit. So he's [Benoit Blanc] a famous private detective. They make reference to, 'You solved that case with the tennis champ.' At the beginning of Sleuth, the novel that he's dictating is Death by Double Faults. And he's describing how the killer like paced along the line of the tennis court and threw the body like into the clay."

In the scene where the dogs run from the mansion in slow motion, the trainer held both dogs by the collar at their mark on the side of the estate driveway. The other trainer stood at the end point for dogs across the lawn. On action, the other trainer stood up and waved his arm to get the dogs attention. On action, the first trainer released dogs giving the command "Go to." The dogs ran across the yard to the other trainer who placed pieces of kibble in two bowls for dogs as reward.

Due to limited resources, American Humane Association did not monitor some of the dog action.

The first name of Benoit Blanc is possibly a reference to Benoît B. Mandelbrot, a mathematician whose name is given to complex fractal diagrams having an infinite degree of complexity.

the type of phone that a character uses hints at their guilt or innocence.

Jamie Lee Curtis and M. Emmet Walsh also starred in Christmas with the Kranks (2004) where they played neighbors. In this movie they do not share any screen time together.

M. Emmet Walsh also played a security guard in Frasier: Bully for Martin (2001) of Frasier (1993) as Martin Crane's crotchety boss.

Joseph Gordon-Levitt: The police detective heard on the television series Marta's sister is watching, billed in the film's credits as Detective Hardrock. Gordon-Levitt has appeared in five of the films Rian Johnson has directed.

Gary Tanguay: When the news crews gather outside Marta's home, a clip is shown of a reporter on the TV broadcasting from outside the house. The reporter is a local New England sports talk show host.

Rian Johnson: [cousins] Rian's cousin Mark Johnson did the title credits and based the font on an Agatha Christie series of paperbacks. Zack Johnson is another cousin, and he painted the cast paintings for the end credits.

Rian Johnson: [music] Rian's cousin Nathan Johnson, composed the film's score, as he's done for all of the director's films "except Star Wars: Episode VIII - The Last Jedi (2017), which he understood." It was the composer's first time using an orchestra.

The message Harlan leaves for Linda in the envelope written with invisible ink (which Richard merely saw as a blank sheet of paper when he found it): "My heart, It's time to cut the dead wood. He's cheating on you. I have proof. I know you don't need to see. Untether yourself. It's time - Dad."

While filming the big reveal at the end of the film, Rian Johnson was surprised to discover that Daniel Craig had completely memorized the last 30 pages of the script, most of which are a monologue delivered by his character. Johnson ended up altering the way he shot the scenes, favoring long takes instead of shorter cuts, because he found that Craig's performance became better and better the longer each take became.

When Marta is in Ransom's house for the first time, we see a row of four or five brown-tinted glass jugs in the background. There is, however, an empty space in the row where another jug might have been. By the climax of the film we see in a flashback that Ransom has used the jug to burn down the medical examiner's office.

The first time Marta is seen at the Thrombey house, she is looking upwards at the house and members of the family from the driveway. In the last scene, the surviving members of the Thrombey family are all standing in the same spot in the driveway, looking up at Marta on the balcony, nicely signifying that the roles have been reversed.

The steelbook of the film's Blu-ray has a transparent protective slip cover. On the back of that cover are a series of knives arranged in a way to form a circle, pointing like arrows at a certain direction. The steelbook has the film's poster printed on it, where all of the characters are seen. As an easter egg, when the cover is flipped and then put on the steelbook again, the knives will point to the culprit.

Harlan Thrombey asks Marta how she always beats him at Go, she responds "you're playing to win, I'm playing to build a beautiful pattern." This nicely foreshadows Marta's arc; while the Thrombey family members try to lie, cheat, and manipulate their way into inheriting Harlan's estate, Marta is the only person who repeatedly attempts to do the right thing even at her own expense. She ends up inheriting everything, thus, she "wins."

At one point, a baseball on Harlan's desk is picked up and thrown out the window of his office. Roughly around the same time in the movie, Benoit Blanc states "the game is afoot" referencing the old Sherlock Holmes' phrase meaning the search continues. The baseball then continues to pass from character to character in one way or another. The baseball represents the "game being in play" and when the mystery is finally solved the ball goes back onto the desk symbolizing the end of the game/search. This is also a metaphor for Harlan's love of games and his one last hurrah. (Arthur Conan Doyle was himself quoting from Shakespeare's "Henry V", when the eponymous king is exhorting his men to continue the attack on Harfleur.)

Harlan dies on his 85th birthday. This is a reference to Agatha Christie who died at the age of 85. This film is a tribute to Christie's writing style and stories.

Working out the mechanism by which to handle and explain Marta's switching up the drugs is the script element that kept Rian Johnson frustrated the longest. "I need something where both she and the audience crucially need to believe that she has messed up, and through her error has killed him, but it needs to be something that I can effectively undo at the end of the movie." He says he went through lots of overly complicated variations before settling on the finished element.

At various points in the movie, members of the Thrombey family refer to Marta as being from Cuba, Ecuador, Paraguay, Uruguay, and Brazil. Though it is insinuated that Marta herself was born in the United States (by characters stating that only her mother is "an illegal"), Marta never corrects them, nor is it ever reliably stated where her family originated.

Harlan Thrombey foreshadows the ending when he mentions to Marta that the carefree lifestyle of his grandson Ransom makes him unable to tell a prop knife from a real one. In the climax, Ransom attacks Marta with a knife that he impulsively grabbed from the knife chair, only to find out that it is a prop knife.

That last glimpse of Harlan's portrait at (2:04:00) is tweaked a little "leaving everything feeling okay." He's now smiling.

When Benoit Blanc is first seen by the audience, he is sitting in the study listening to Lieutenant Elliot question the Thrombey family members, playing the same note on the piano at seemingly random intervals. This is not random at all; after Blanc hits the piano key Lieutenant Elliot always asks the same question; "What time did you arrive at the house?" The piano key is Blanc's signal to Elliot to ask the question.

Towards the end of the movie, Linda Drysdale reads a letter written to her (in invisible ink) by her father. She mentions this in the initial interview with the police: "we had our own secret way of communicating"

Early on, Harlan makes a remark about people "impulsively unraveling the strings on their parachutes." This very habit winds up being his own undoing, with his shooting down of Marta calling the ambulance, which would have saved his life had he listened to her instead of indulging in his flair for the dramatic.

Rian Johnson decided early on that he wanted a PG-13 rating for the film, so he had to remove the f-bombs from his original script. He also originally wanted the throat slice to be "a very expressive, expressionistic red splash" towards the audience, but the MPAA gave them an R which forced him to drop it completely.

When Ransom is reading over the blackmail letter meant for Marta, there are several obscured issues of the New Yorker visible on the coffee table. Earlier in the film, Linda and Joni reference the New Yorker article on Blanc's career, further hinting at Ransom being the one who hired Blanc to investigate the death.

(At 30 mins.) They had to re-shoot the shot of Walt Thrombey smoking his cigar on the porch because the character in the window behind him was too clear - it's later revealed that it's Marta, so they further obfuscated it by having Daniel Craig's stand-in don the robe instead.

In some closeups, Blanc appears to have some redness on his neck. In a deleted scene, Blanc explains to Joni that he had ordered and used some of Flam's - her lifestyle company - product (Snail Oil Jelly) and developed a rash. He then googled "Flam" and "Rash" and found pages and pages of complaints on beauty sites that Flam products had caused rashes. Blanc also tells Joni that his investigation determined that Flam had been failing for years.

The first time Detective Blanc and Marta meet, Blanc takes a few seconds longer to look at her shoes. Near the end of the film Marta asks Blanc when did he know she had something to do with Harlan's death. And he replies "Oh, from the first moment you set foot in front of me".

No one in the family knows how old Great-Nana is, treat her like a living prop or a burden, and pretty much dismiss her when she mistakes people who walk by as Ransom. While it accurately shows how self-absorbed they are, her testimony at the end exonorates Marta and reveals Ransom's role in Harlan's "suicide" after Blanc shows her kindess and respect, showing how much the family messed up by considering her beneath notice.

They had to digitally paint out some of the blood they used on set for that first appearance of Harlan Thrombey's dead body, in order to secure a PG-13 rating.

Noah Segan recalls the scene where his character grabs Ransom's upper arm "and I could not find purchase his arm muscle was much larger than my hand."

Don Johnson's black eye at is a visual effect added in post-production. The shot right before of Marta holding the coffee mug at (2:04:33) is also an effect "originally you could read the writing on the mug, and we realized it tipped it, the last shot didn't have the same impact if you'd already seen the words and so our effects guy basically moved her hand so it was covering the words so we got the final little reveal."

The circle of knives positioned behind the chair during the opening interviews and the final reveal is donut shaped with a hole in the center. This is just like Detective Blanc's metaphor for the mystery. All of the knives face toward the center, signifying how all of the characters have their "knives out" and are battling to discover the hole in the mystery.

Ransom says that he thought he was the only one who ever beat Harlan at Go. This sets up the final confrontation between Ransom and Marta, showing that she is smarter than he is and allows her to trick him into giving an engineered public confession.

According to Marta's cellphone and the toxicology report, the film takes place in November 2018. According to dialogue, Harlan's birthday party was November 8.

The way the light catches the letter Harlan had planned to give Linda briefly shows that it isn't blank. Later, Linda picks up a stack of letters from her father's desk on the same letterhead. The letters all show heat damage from Linda's lighter. It's later revealed that a message was left on the letter in invisible ink.

Apple agreed to have their products used in the film, on the condition that no Apple products could be used by the killer. Notably, Marta does not use any Apple products, further enforcing the idea that she was responsible for Harlan's death until the final reveal.

A deleted scene explains Walt's limp. He tells the detectives that he had suffered a bicycle accident. However, after his wife Donna spots a menacing man on her front porch - a scene in the trailer but not the movie - Blanc confronts her with evidence that Walt had been shot in the leg and that while being shot while bicycling was a possibility, the couple had "at the very least buried the lede". Donna then admits that Walt had lost heavily in investments and was embezzling money from Harlan's publishing company to cover his losses.

At the epilogue, Linda Thrombey decrypts the message Harlan left her, exposing the affair of her husband Richard, and stares at him dejectedly. Shortly after, in the very last scene, Richard is seen sporting a black left eye, implying that Linda is the one who caused it.

At the reading of the will, Ransom is shown smirking while playing with a chessboard. He's the 'chessmaster' of the film, the one who orchestrates the entire plot to kill Harlan and frame Marta for it. Chess is also a game you can only win by playing to win. When he's in control, he can manipulate Marta effortlessly, but whenever she acts on her own, playing her game her way, she sticks to the beauty and benevolence of her style of Go.

During the car chase scene Ransom calls Marta "Baby Driver (2017)" due to her reckless driving. Since Rian Johnson felt "there's no way we're going to top anything in that" he decided to go the opposite route and deliver a silly chase.

When Marta and Harlan play Go, she tells him that she always beats him because he plays to win and she plays to make a beautiful pattern. Several times Marta unknowingly foils Ransom's plans by being a good and kind person rather than acting as selfish as the rest of the family.

As Blanc is going over certain events on the night of Harlan's death, it's shown that during the night, Meg was woken by the sound of the family dogs barking. This is one of the only details that isn't explained by the flashback of Marta covering up Harlan's death, since the dogs liked her enough to be silent when she was sneaking through the yard. It's later revealed that they were barking at Ransom, who was attempting to sneak in to switch back the medication bottles.

In the restaurant scene, "Sundown" by Gordon Lightfoot is playing softly in the background. Its chorus says, "Sundown, ya better take care, if I find you creepin' 'round my back stairs," referring to both of the people in that scene who have used the lattice on the outside of the house to get to the secret door that led to the study.

At the start of the movie, the housekeeper is seen making breakfast and pouring coffee into a mug that says "My house, my rules, my coffee", shortly before she finds Harlan's body. At end of the movie, when Marta is standing on the balcony of what is now her mansion, with the Thrombey family members looking up at her, she is drinking from the same mug, with her hands covering all the words except "My house."

Eagle-eyed viewers will spot a particularly piece of foreshadowing when the security footage is viewed. Despite having stormed out of the party early, Ransom's car is never seen heading down the driveway.

The firefighters extinguishing the fire at the medical examiner's office are all present or former members of the Marlborough, Massachusetts Fire Department. Paul Zompetti and Ron Ayotte are both former fire chiefs, Brian Leonard is a lieutenant, and Joseph Bisazza is a firefighter. Their names are visible on their coats.

Ransom forces all the Thrombeys' employees to call him "Hugh" because he's an asshole. This hints at the fact he is just as racist and unpleasant as the rest of the family, with his kindness to Marta only being an act.

Benoit tells Marta, "The game is afoot, eh Watson?" He's recalling Sherlock Holmes, but we also find out later he's suspected Marta ever since she stepped foot in front of him - he noticed the drop of blood on her foot. Arthur Conan Doyle was himself quoting from William Shakespeare's "Henry V", when the eponymous king is exhorting his men to continue the attack on Harfleur.

It is revealed that the mansion was purchased in the 1980s. The keystone in the arched balcony door above the entryway has a monogram of the letter I superimposed over the letter T. This means that the house was built by someone whose initials were T.I. Obviously, it was not the ancestral home of the Thrombeys.

At approximately 22:10 Richard flips the letter (the one Harlan wrote for his daughter Linda) and you can briefly see light go through it, indicating the use of invisible ink to inform Linda of Richard's misdeeds.

In the scene at the bar, after Marta tells Ransom her side of the story, 3 beer bottles with green labels can be seen on Ransom's side of the table and 1 bottle with a red label on Marta's which is a reference to the atari position in the game of Go which is a recurring theme in the film. In Go, atari is a situation in which a player's stones are enveloped by the adversaries' with only one exit possible, effectively putting them in an advantageous position for the very next move. Had Ransom given Marta up to the authorities, the rest of the family would end up receiving all of the wealth left to her in the will and Ransom would get nothing. By acting as her savior in the pickle that she is in (in exchange for a cut of the wealth he would otherwise not see a penny of), he's deliberately letting her off the hook from a position of atari which in and of itself is a suspicious move coming from an "expert" go player and foreshadows his malignance. Moreover, letting go of a position of atari is seldom not a lousy move and ultimately proves that Marta is in fact a "better Go player than Ransom", like Harlan claims.

During the will reading scene; as Alan, Harlan's lawyer, details the aspects of Harlan's will; the camera focuses on a Thrombey family member and their own family, this tells us visually what they want from Harlan's will. When Alan talks about Harlan's Mansion, the camera cuts to Linda and Richard, which shows that they want to inherit the mansion. (Which makes sense as Linda is a real estate mogul) When Alan talks about Harlan's gargantuan fortune, the camera cuts to Meg and Joni, which shows they want It. (Especially since they need it for Joni's business and Meg's college tuition) and finally, The camera is focused on Walt and his family when Alan talks about the publishing company, showing that Walt wants to run it again despite his father firing him.

The film contains at least two Sherlock Holmes references (use of the catchphrase "the game is afoot," and Marta is referred to as Watson); Christopher Plummer played Sherlock Holmes in the film Murder by Decree (1979), and also spoke the line "The game's afoot" in Star Trek VI: The Undiscovered Country (1991) as the Klingon General Chang. (Arthur Conan Doyle was himself quoting from Shakespeare's "Henry V", when the eponymous king is exhorting his men to continue the attack on Harfleur.) There are at least two more: When Plummer's character tells Marta that the dogs won't do anything (won't bark) when she returned, since they knew her. This is a hat tip to the famous exchange between Holmes and the inspector in the Silver Blaze (the main clue which led to the real criminal): "There is also the curious incident of the dog in the night time" "But the dog did nothing in the night time" "That is the curious incident" Also, the footprints in the mud seemed like a reference to Holmes' legendary footprint analysis that was seen in so many of his stories.

Marta said she has to puke at the thought of lying and did so earlier in the movie. When interrogated by Blanc, she didn't puke immediately, but at (0:44:45) you can hear her stomach.

The fact the blackmail letter is torn across the bottom is extremely easy to dismiss when Marta opens it, but becomes very relevant during the reveal.

When conducting the interviews, all the Thrombey family members are seated with the chair to the outside of the knife circle, towards the handle. When Marta is interviewed however, the chair is positioned dead centre of the knife circle, at the blade points. This is symbolic of the way the Thrombey family all turn on Marta.

Katherine Langford filmed a scene for Chris Evans' previous movie Avengers: Endgame (2019) as the older version of Morgan Stark. The scene was deleted and only released via the Disney+ streaming service.

None of the family members would have profited at all from Harlan's death, because that would mean losing their income. Ransom is the one with the least stakes out of the family, and thus, has no such compunctions killing Harlan.

The film closes to the sound of The Rolling Stones, a British band playing American music, much as the lead actor Daniel Craig is a Brit playing an American character. The song, "Sweet Virginia", has the line "got to scrape that shit right off your shoe", which might also be a nod to the blood spattered on Marta's sneaker.