Acting for Two: Robert Downey Jr. plays 4 characters: CIA agent Claude, filmmaker Niko, Professor Hammer and Congressman Ned Godwin. While the characters are kept separate for the most part, the third episode reveals that they all know each other and they meet up at a restaurant to introduce the Captain to Niko since Claude wants him to serve as a consultant on Niko's upcoming film.
Banned in China: The series is banned in Vietnam and any mention of it is censored by state media because they believe it's black propaganda against the Communist Party and the State.
California Doubling: The Vietnam scenes were filmed in Thailand, since the Vietnamese government denied the filmmakers' attempts to get a filming permit there.
Fake American: While the Captain isn't technically American, he still speaks English with an American accent due to having gone to college in California. He's played by Hoa Xuande, who's Australian.
Fake Mixed Race: Hoa Xuande, who is of fully Vietnamese descent, as the half white/half Vietnamese protagonist. To alleviate this Xuande dons colored contacts and has dark brown hair while playing the Captain.
Serendipity Writes the Plot: In the book, The Hamlet was filmed in the Philippines, much like how Apocalypse Now was. Budget restraints meant that the show had to use Napa County in California as the filming location instead, which actually ended up working in the show's favor since they could bring several supporting characters on to play the background extras in The Hamlet.
after the book won a Pulitzer Prize. Instead, it doesn't have an official Vietnamese translation.