[7][8] The film stars the voices of Ming-Na Wen, Alec Baldwin, Donald Sutherland, James Woods, Ving Rhames, Peri Gilpin, and Steve Buscemi, and follows scientists Aki Ross and Doctor Sid in their efforts to free a post-apocalyptic Earth from the Phantoms, a mysterious, deadly alien race who has driven the remnants of humanity into "barrier cities".

Square intended to make the character of Aki Ross into the world's first photorealistic computer-animated actress, with plans for appearances in multiple films in different roles.

The surviving humans live in "barrier cities" protected by energy shields that prevent Phantoms from entering, and are engaged in an ongoing struggle to free the planet.

Aki searches for the sixth spirit in the ruins of New York City when she is cornered by Phantoms but rescued by Captain Gray Edwards (Alec Baldwin) and his squad Deep Eyes, consisting of Master Sergeant Ryan Whittaker (Ving Rhames), Neil Fleming (Steve Buscemi) and Corporal Jane Proudfoot (Peri Gilpin).

Returning to her barrier city, Aki joins Sid and appears before the leadership council along with General Douglas Hein (James Woods).

To scare the council into giving him clearance to fire the Zeus cannon, Hein lowers part of the barrier shield protecting the city.

Sid finds the eighth spirit at the crater site of the alien asteroid's impact on Earth at the Caspian Mountains.

[11] In order to keep the film in line with Hironobu Sakaguchi's vision as director, several script rewrites took place,[17] most in the initial stages of production.

[6] Director Sakaguchi named the main character after his mother, Aki, who died in an accident several years prior to the production of the film.

[13] He later explained that the theme he wanted to convey was "more of a complex idea of life and death and spirit", believing that the best way to portray this would be to set the film on Earth.

[31] Dan Mayers from Sight & Sound said that the film followed the same theme typically found in Final Fantasy video games: "A party of heroes averts impending global holocaust by drawing on their individual skills, gaining knowledge through challenges and emerging victorious with new-found love and respect for themselves and their companions".

[35] Sato perceived Aki's original look as a "supermodel", and subsequently removed her make-up and shortened her hair in order to give her a more intelligent look that would "convince people that she's a scientist".

The short film, appearing in the DVD's bonus content and featuring her with a slightly modified design, shows her acrobatically dueling a robot from the Matrix setting.

[38] Elliot Goldenthal composed the entire score, as well as the film's theme song, "The Dream Within",[13] which had lyrics written by Richard Rudolf and vocals performed by Lara Fabian.

[40] In the liner notes to the album, Goldenthal describes the soundtrack as combining orchestration techniques associated with the late 20th-century Polish avant-garde, as well as his experiments from Alien 3, and 19th-century Straussian brass and string instrumentation.

[41] In the film's 'Making of' featurette, Goldenthal states he used "ghostly choral" music when the Phantoms are emerging, in an attempt to give a celestial feeling, and focused on low brass clusters and taiko drum rhythms for violent scenes.

[42] Christopher Coleman from Tracksounds gave the soundtrack 10 out of 10, saying the feel of the album was "expansive and majestic" and that the score elevated the viewing experience of the film.

Chris Taylor from Time magazine noted that video game adaptations had a poor track record at the box office and that it was Sakaguchi's first feature film.

[51] The film achieved average to poor results at the box office in most of Southeast Asia; however, it performed well in Australia, New Zealand and South Korea;[52] 160,100 tickets were sold in Seoul City.

[60] Writing in a 2007 article about the uncanny valley, John Mangan from The Age cited character's eyes in the film as an example of this phenomenon, where attempts to create realistic humans unintentionally cause revulsion;[61] Peter Travers from Rolling Stone said that it was enjoyable watching the characters at first, "but then you notice a coldness in the eyes, a mechanical quality in the movements".

Describing the dialogue as "passable", Nell also said the script read like a reject from Pokémon, and that its "confusing gibberish about the earth's spirit [would] not do justice to the beliefs of environmentalists or pantheists".

[63] Todd McCarthy from Variety gave a positive review, praising the voice work and visuals though saying the characters were no more emotionally expressive than those in traditional animation.

[67] Ruth La Ferla from The New York Times described her as having the "sinewy efficiency" of Alien franchise character Ellen Ripley and visual appeal of Julia Roberts' portrayal of Erin Brockovich.

[68] The book Digital Shock: Confronting the New Reality by Herve Fischer described her as a virtual actress having a "beauty that is 'really' impressive", comparing her to video game character Lara Croft.

[6] Writing in the book Action and Adventure Cinema, Marc O'Day described her as among the "least overtly eroticised" female characters in science fiction, though stated that Aki was "transformed in a variety of poses into an erotic fantasy machine" in a bikini photo shoot that was included on the DVD's special features.

[74][75] In 2011, BioWare art director Derek Watts cited The Spirits Within as a major influence on the successful Mass Effect series of action role-playing games.

[79] Edited by Steven L. Kent, the 240-page color book contains a foreword by director Sakaguchi and extensive information on all aspects of the film's creation, including concept art, storyboards, sets and props, layout, motion capture and animation, as well as a draft of the full script.

[82] Conversely, the film was also nominated in the worst screenplay category at the 2001 Stinkers Bad Movie Awards, but lost to Pearl Harbor.

[30] The DVD was initially a top seller; in February 2002, Jun Aida said that while sales were still strong, they were not good enough to save Square Pictures from closing.

[73] Both versions contained two full-length commentary tracks (one featuring Motonori Sakakibara, sequence supervisor Hiroyuki Hayashida, lead artist Tatsuro Maruyama, and creature supervisor Takoo Noguchi; the second featuring animation director Andy Jones, editor Chris S. Capp, and staging director Tani Kunitake)[86] as well as an isolated score with commentary.