Burt Bacharach's bouncy theme is a marvelous piece of '60s kitsch, and is probably better known than the film itself. Played by Herb Alpert and the Tijuana Brass, everyone!
Ironically, this is the only Bond movie to date (canon or no) to have spawned two hit singles, as both the instrumental theme music and Dusty Springfield's Breakaway Pop Hit "The Look of Love" charted.
Vesper Lynd appears to be disposing of a body when Evelyn comes to her house. This is never mentioned or referred to again.
The UFO. Just... what?
Bizarro Episode: Many things in the film are never mentioned again once they happen. It is all completely over the top even for psychedelic sixties spy flicks. Many scenes could be removed from the film with little or no damage to the plot. There are even some scenes that when seen together have absolutely nothing to do with each other. But somehow it fits together as a whole. You can blame this completely on the film's fascinating Troubled Production. Those five directors listed in the credits? None had any contact with each other, and none were working with a complete script. Plus, Peter Sellers was originally supposed to be the star, but either quit or was fired depending on who you believe, prior to filming several important scenes, so the film was awkwardly retooled to center around David Niven instead.
Cliché Storm: Referenced when Sir James Bond turns down the entreaties of the secret service heads of the superpowers, telling them "If I may interrupt this flow of cliche, it is now that time of day that I set apart for [playing] Debussy."
Ending Fatigue: Arguably starts when Evelyn Tremble and Le Chiffre are killed. The remainder of the film has to bring all the other characters together to unmask and confront the Big Bad. The resultant climax degenerates into a gigantic free-for-all fight in the casino with a Kill 'em All ending played for laughs, followed by a Fluffy Cloud Heaven ending.
Jimmy Bond:[as he's being led to a firing squad] You can't shoot me! I have a very low threshold of death. My doctor says I can't have bullets enter my body at any time.
The main villain's diabolical plan: to release a virus that would make all women beautiful and kill every man taller than he is. Considering Jimmy Bond is the shortest character in the whole movie, this is a dangerously lethal diabolical plan.
During the Mind Screw Le Chiffre imposes on Peter Sellers' Bond, Bond imagines himself marching about with Scottish bagpipers. When one of the bagpipers asks Bond if he is Richard Burton, Bond replies "No, I'm Peter O'Toole." The kicker is that the bagpiper is actually played by Peter O'Toole in a cameo. The bagpiper then answers "Then you're the finest man that ever breathed!"
It's mentioned in the film that there have already been multiple new James Bond 007s after the original since none had the original's survival skills. It was already quite clear that Sean Connery would not play James Bond 007 anymore after the same year's You Only Live Twice, but nobody could have known the main series would go through five Bond actors altogether (it's on its sixth with Daniel Craig, who started with the official and much-better-received classic Casino Royale in 2006).
The plot to replace infuential persons with clones under the villain's control was later done straight in the 007 game Agent Under Fire.
Mis-blamed: Despite EON having nothing to do with this version of Casino Royale, the film's critical failure and early release led to Fan Dumb savaging them for its poor quality. This permanently turned Albert Broccoli and his daughter off of anything Bond related that wasn't under their control, which became their rallying motive for the long and messy legal battle with McClory that only started ebbing when he died in 2006 and ended with his estate giving the last remnants of Bond to them in 2013, almost 50 years after this movie's release.
Took the Bad Film Seriously: Peter Sellers, because he was cast when it wasn't going to be a spoof. His performance is funny in a mostly-deadpan way, but he's not on the same wavelength as most of the rest of the cast. This is also one of the few places where you can hear his natural speaking voice.
"Weird Al" Effect: The score's cue "Bond Street" is probably better known to younger viewers as the music that plays during Stewie's "sexy parties" in the early episodes of Family Guy.
What Do You Mean, It Wasn't Made on Drugs?: The film could best be described as "James Bond on massive amounts of acid" but had a fairly respectable creative team behind it. Aside from being a spoof, much of the effect comes from creative issues leading to there being five different directors whose scenes did not mesh very well. The ending includes a UFO, Frankenstein's Monster, cowboys and Indians, a flying roulette wheel, a monkey, and a seal. Add in the firing of Peter Sellers which lead to a new framing sequence interspersed with the original footage.