- Acting for Two: Peter Sellers also played Jessica Marbles' taxi driver, but the scene was deleted.
- All-Star Cast: Peter Falk, Eileen Brennan, Alec Guinness, David Niven, Peter Sellers, Dame Maggie Smith, a young James Cromwell, and a rare acting appearance by Truman Capote.
- Deleted Role: Phil Silvers had a small role in this film, but his scenes were deleted in the final release print.
- Deleted Scene: Several additional scenes were included in the film's network-TV airing. None are available on the DVD release, but all can be found (albeit in poor a/v quality) on YouTube.
- Dick and Dora Charleston encounter Tess Skeffington traveling on foot en route to Lionel Twain's. See here.
- Miss Marbles converses with a taxi driver (also played by Peter Sellers, using his Willium "mate" voice) on arriving at Twain's. See here.
- Willie Wang gloats about discovering his own "clue", which turns out to be worthless. See here.
- Finally, expies of Sherlock Holmes and Dr. Watson arrive late, after the whole thing is over. See here.
- Fake Nationality:
"Never underestimate a Frenchman's nostrils, Miss Twain.""I'm not a Frenchy! I'm a Belgy!"
- British actor Peter Sellers as a Chinese detective. Likely a parody of how Charlie Chan had never been played by a Chinese actor (in live action). It is later revealed he was actually either Lionel Twain's illegitimate son or adopted and raised by Twain. In either case, no explanation is given for his speech.
- American actor James Coco plays Milo Perrier, who (depending on which line of dialogue you believe) is either a Frenchman or a Belgian.
- Not to mention fellow American James Cromwell as Perrier's chauffeur Marcel.
- Follow the Leader: A 1980 television movie titled Murder Can Hurt You! took this film's concept and aimed it at '70s police shows with characters such as Nojack, MacSkye, Lt. Polumbo, Sgt. Salty Sanderson, and Studsky & Hatch.
- Old Shame: Peter Sellers hated the script and thought the movie would be an absolute bomb. It was a smash hit.
- Playing Against Type: Sir Alec Guinness as a strange butler may surprise people, as well as Peter Falk playing a Humphrey Bogart-style hard-boiled detective instead of his usual Columbo.note
- Quote Source: Stranger Behind the Mask
- Spared by the Adaptation: depending on whether you think a murder actually happened in the film (other than of a good weekend). There was a novelization of the movie released at the time. It backs off some of the films absurdist elements, for example showing that the butlers name was James Benson and the whole Jamessir Bensonmum exchange was just him messing with the detectives on Twains orders. In the same vein, it changes the films Gainax Ending by having both the butler and the maid walk into the room following Twains The Reason You Suck speech, revealing that all of the Twain household are alive and well, so no one actually died and it was all a con on the detectives.
- Stunt Casting: Novelist Truman Capote as Twain.
- Those Two Actors: Peter Sellers and David Niven had previously costarred in The Pink Panther (1963) and Casino Royale (1967).
- What Could Have Been:
- Orson Welles was originally considered to play Sidney Wang but had a scheduling conflict.
- Myrna Loy was originally offered the part of Dora Charleston but she declined, later stating that "it would have been ridiculous to have Myrna Loy doing Myrna Loy". She also stated that she didn't want her "ass pinched by David Niven".
Trivia / Murder by Death