All-Star Cast: Not that it helps at all in this particular movie's case...
Awesome, Dear Boy: Halle Berry originally said that she did the film because she wanted the awesome experience of playing a woman beholden to no one. However, in an illustration that Hollywood acknowledges the power of this trope, it turned out that she was only saying this for publicity's sake; she later gave an interview saying that she mainly did it because she was under contract (thus beholden to people).
Box Office Bomb: It only brought back over $80 million of its over $100 million budget, making it a spectacularly expensive failure.
Creator Killer: This film killed whatever hopes its director, Pitof, might've had of breaking into American cinema as a frontline director. Pitof has only directed one more film since, and it's a TV movie.
Genre-Killer: The failure of both this film and Elektra was a major reason that studios became so skittish about female superhero movies. Of course, this has resulted in numerous accusations that it was just being used as a cheap excuse, acting like their both being such awful movies couldn't be a factor in no one wanting to see them. It took the DC Extended Universe's Wonder Woman more than a decade later to eventually prove that a female-led superhero movie can succeed critically and financially.
First of all, I want to thank Warner Bros.. Thank you for putting me in a piece of shit, God-awful movie[...] It was just what my career needed.
The context for that quote: She said it at the Razzies as she accepted her award for "Worst Actress". The entire time, she was holding her Oscar for Monster's Ball in the other hand, publicly reminding people that she is usually a good actress; the movie was just THAT bad. Razzies founder John Wilson even remarked that after seeing this, he expects Berry to run for the Oscar again.
In addition to Berry, the film also became a big shame for co-writer John Rogers.
This also happened with one of the film's VFX vendors, Tippett Studio, who actually went out of their way to point out that the only effects they did in the film were the cats. They've since furthered their distance from the film by not even making any mention of it on their site.
As often noted on the web, the film bears a striking resemblance to The Crow. In fact, the movie's first trailer was alleged to have the same narration script as The Crow's own trailer - only changing the respective animal.
The romantic basketball game between Patience and the detective was lifted verbatim from Daredevil.
Screwed by the Lawyers: According to one of the writers, "insane legal issues" prevented Selina Kyle being the main character.
Halle Berry signed for a sequel but after all the bad reviews, development on the sequel was quickly squashed. This also made her available for the thirdX-Menfilm; she rejoined that series, but allegedly got paid less for her role that go round.
The film also managed the impressive feat of killing off an unrelated series before it could even really begin; a film starring Berry's Die Another Day character Jinx had been in development for the previous two years, but the critical and commercial failure of this film killed that one too.
The film was originally a spinoff from Batman Returns, and would have followed Selena (intended to be played once again by Michelle Pfeiffer) as she supposedly took on a new enemy during a stay at a resort. The script was written by Daniel Waters and completed in 1995 (ironically, on the same day Batman Forever was released), but both Tim Burton and Pfeiffer dropped out soon after and the film was stuck in Development Hell for years. By the time it was picked up, a law had been passed against making good superhero movies or something.
Ashley Judd and Nicole Kidman were originally considered to play Patience, and the character's surname was originally Price.
An early draft of the script had Patience becoming Catwoman to avenge her mother's death.
Originally, "Outrageous" from Britney Spears was supposed to be the single from the movie. However, Britney injured her knee while filming the music video. With no video to promote the single, they instead used "Scandalous" by Mis Teeq.
The scrappedDirect-to-Video animated spinoff film would've had Patience meeting Selina along with delving deeper in the Egyptian mythology of the film, which would've satisfied fans of the titular character.
This movie managed to become the second comic book movie and the first superhero-themed one to win the Worst Picture Razzie; 2015's infamous attempted Fantastic Four reboot became the second superhero film and third comic-book movie 11 years later. The other comic-book movie with a Worst Picture Razzie is 1986's Howard the Duck.
Trivia for the comics:
Creative Differences: Ed Brubaker reportedly left his critically-acclaimed early-2000s run writing Catwoman's solo title in protest at the replacement of early artists like Cameron Stewart and Rick Burchett with the much more Fanservice-heavy work of Paul Gulacy. An interview in which Gulacy described Selina as "slutty" and the idea of her not being primarily a fanservice character as "absurd" may have been a final straw.