Kaneshiro Takeshi spoke four languages himself in this film. His narrations were all in Mandarin, most of his live lines are in heavily-accented Cantonese, he spoke Japanese when he called one of his ex-girlfriends, and had one line of English when he apprehended a suspect (he said "hands up!" to him). He used all 4 when he approached Bridgett Lin's character.
The title is an amalgamation of two "landmarks" in Hong Kong. 1) Chungking Mansions, a drug-filled, rundown hostel populated by Indians, Pakistanis and Nepalese. 2) Midnight Express, a Indian fastfood store in Lan Kwai Fong, a major bar district populated by foreign yuppies (Tony Leung vists California, a bar located directly across the street from it).
The script for arose within the two month period when production on Wong Kar-Wai's film Ashes of Time was slow and was interrupted for those two months. Wong Kar-Wai need a script to fulfill his contract for a second feature. Chungking Express is that second feature.
Was the Criterion Collection's first Blu-ray release, along with Bottle Rocket (1996), The Third Man (1949), and The Man Who Fell to Earth (1976). With the exception of the former film, all of the titles have since gone out of print.
The trivia item below may give away important plot points.
The original ending involved Faye meeting Cop #633 at the airport and the two characters flying off to another country. However, when Wong couldn't agree terms for his ideal location in an airport, he decided to opt for an ambiguous ending.