It features two intertwined storylines—one tells the story of a hitman wishing to leave the criminal underworld (Leon Lai), the prostitute he starts a relationship with (Karen Mok), and his agent (Michelle Reis), who is infatuated with him.

The other story is of a mute ex-convict on the run from the police (Takeshi Kaneshiro) and a mentally unstable woman dumped by her boyfriend (Charlie Yeung).

Set in 1995 pre-Handover Hong Kong, Fallen Angels explores the characters' loneliness, their alienation from the situations around them, and yearning for connections in a hectic city.

Wong initially wrote Fallen Angels as the third story of his preceding film, Chungking Express (1994), but split them into two separate projects due to their cumulative length.

Cinematographer Christopher Doyle extensively used wide-angle lens to distort the characters' faces on the screen, conveying their isolation from the surrounding world.

The soundtrack extensively uses trip hop and pop songs to convey mood and maintain an "urban environment" that plays with popular culture.

Retrospectively, critics commented that though Fallen Angels was not as groundbreaking as its predecessor, it remained one of Wong's most captivating films, cementing his trademark styles.

Since its release, Fallen Angels has encompassed a large cult following, and is notable for being the last film Wong fully shot in his native Hong Kong before embarking on more ambitious international productions.

Increasingly frustrated by the monotone, futile life of contract killing and his lack of free will, Wong quits and sets up a meeting with his partner but no-shows.

Certain that she will show up at the bar in a couple of days looking for him, he asks the bartender to suggest a piece of music on the jukebox called "Forget Him" (忘記他) with the number "1818".

Meanwhile, Wong has a late night meal at McDonald's, where he encounters an eccentric woman nicknamed "Blondie", who sits next to him and invites him into her apartment.

The chaotic Chungking Mansions, where the hitman's partner lives, is also home to Ho Chi-mo, an ex-convict who has escaped prison and is on the run from the police.

He falls back into abusive habits, going so far as to cut off the hair of a man whose family he in the past forced to eat an excessive amount of ice cream.

As they ride through early-hours Hong Kong they cross through the Cross-Harbour Tunnel in scenes evocative of those of Ho Chi-mo and Charlie earlier in the film, with the light of dawn being the only instance of daytime in the movie.

[6] After the release of Chungking Express, Wong noted that the story of a lovesick hitman still interested him, and so he decided to develop it into Fallen Angels.

Wong also decided to "gender-reverse" the attributes of the roles in his new film, with the gun-wielding attributes of Brigitte Lin in Chungking Express being manifested in the hitman Leon Lai would play, while the sneaking-in of Faye Wong in Chungking Express to other apartments was reversed by Takeshi Kaneshiro's character sneaking into shops and businesses in Fallen Angels.

Wanting to also try to differentiate it from Chungking and to try something new, Wong decided along with cinematographer Christopher Doyle to shoot mainly at night and using extreme wide-angle lenses, keeping the camera as close to the talents as possible to give a detached effect from the world around them.

The film also makes use of "claustrophobic" shots involving fast and slow camera movements in a frenetic pace interpolated within crowded, chaotic locations in Hong Kong.

A particularly heavy theme of Fallen Angels is the city itself, with "bedazzling shots" of sites associated with 1990s Hong Kong such as neon-lit billboards and now-closed Kai Tak Airport, as well as the city's visual landscape and 1990s uncertainty and anxieties present in its population at the time because of the looming handover of Hong Kong to China overwhelming the mood and feel of the film.

And I said, 'The main characters of Chungking Express are not Faye Wong or Takeshi Kaneshiro, but the city itself, the night and day of Hong Kong.

Also featured in the Fallen Angels soundtrack is a dream pop version of "Forget Him" sung by Shirley Kwan, a reworking of the classic by Teresa Teng, and one of the very few "contemporary" Cantopop songs ever used by Wong Kar-wai in his films.

[21] Stephen Holden of The New York Times said the film relied more on style than substance and wrote: "Although the story takes a tragic turn, the movie feels as weightless as the tinny pop music that keeps its restless midnight ramblers darting around the city like electronic toy figures in a gaming arcade.

In the Village Voice, J. Hoberman wrote:The acme of neo-new-wavism, the ultimate in MTV alienation, the most visually voluptuous flick of the fin de siècle, a pyrotechnical wonder about mystery, solitude, and the irrational love of movies that pushes Wong's style to the brink of self-parody.

Meanwhile, Peter Brunette stated the nonlinear structure and "anti-realist, hyperstylized" cinematography of Fallen Angels and its predecessor Chungking Express pointed towards the future of cinema.

[27] Scholars Justin Clemens and Dominic Pettman commented on the social and political undertones of Fallen Angels: by portraying the characters' loneliness, alienation and indecisiveness,[28] the film represents a metaphor for the political climate of contemporary Hong Kong, the impending end of British rule and transition to Chinese rule in 1997.

[29] Film critic Thorsten Botz-Bornstein highlighted Fallen Angels as a film that represented Wong's peculiar appeal to both traditional "Eastern" and "Western" audiences—it portrays Hong Kong with "post-colonial modernity" showcased through crammed apartments, public transportation, noodle parlors that were emblematic of modern Asia's consumerism.