Set over one thousand years later, the story follows the unnamed protagonist attempting to find a cure for a terminal illness afflicting the girl Yonah—either his sister or daughter.

[3] While traveling the player is frequently attacked by monsters, which include shadowy figures called Shades, large animals, and robots.

[3] Defeating these enemies gives the player experience points that can increase the main character's power, and money that can be used to purchase items.

[5] In addition to the main plotline, Nier includes numerous sidequests, which give the player experience points and money, as well as fishing and farming segments.

[6] In the mid 21st century, in the midst of a snowstorm in summer amid a ruined city, the protagonist fends off ethereal black monsters to protect the sick young girl Yonah—either his younger sister or daughter, depending on the version.

The Gestalt Yonah dissipates to save her Replicant version's life, and the protagonist kills the Shadowlord after Grimoire Weiss sacrifices himself to weaken his power.

Kainé's past is focused on, showing the discrimination she suffered due to her parents' deaths, being born intersex, and later being partially possessed by the rogue Gestalt Tyrann.

Investigating a settlement, she finds its people killed by robots emerging from its central tree, the control unit recording Replicant memories.

[18] The game was designed to have gameplay that would appeal to non-Japanese players in mind, with producer Saito stating that they wanted to depart from menu-based combat.

[8] The soundtrack to Nier was composed by a collaboration of the studio MoNACA, directed by Keiichi Okabe and including Kakeru Ishihama and Keigo Hoashi, and Takafumi Nishimura from Cavia.

Okabe was allowed a great deal of freedom regarding what the music was to sound like; game director Yoko Taro's main request was that he use a lot of vocal works.

Evans wrote songs in versions of Gaelic, Portuguese, Spanish, Italian, French, English and Japanese, where she tried to imagine what they would sound like after 1000 years of drifting.

[30][31] The localizations for the game—in English, French, and German—were produced during development so that all of the versions could be released at the same time, and so that Cavia and Square Enix could solicit feedback from North America and Europe on the game so that it would appeal to players outside Japan.

The guidebook included documentation of in-game elements, developer interviews, and novellas detailing both additional character stories and a post-game ending scenario.

[1] Ito described his work reworking the combat and graphical design as preserving as much as possible while matching his own idealised memories of the game and create something to please fans of Nier: Automata.

[46] The characters were redrawn by Akihiko Yoshida, Toshiyuki Itahana, and Kimihiko Fujisaka; all three had contributed to the Drakengard and Nier series, and were brought in at Yoko's request.

[50] The father protagonist was featured as the player character in the "15 Nightmares" content, originally released as DLC dubbed "World of Recycled Vessel".

[48][46] The Mermaid story, featuring new character Louise, was planned for the original game but cut due to budget and reworked into a later novella.

[52] Most of the English original cast returned, including Laura Bailey (Kaine), Liam O'Brien (Grimoire Weiss), Julie Ann Taylor (Emil), and Eden Riegel (Devola and Popola).

[58] Clements said that "the developers' ideas sometimes outshine the actual implementation", while highlighting the gameplay elements as part of what made the game fun.

[57] Adriaan den Ouden called out the variety as the best part of the game, likening it to a buffet table, while also acknowledging that none of the sections were "amazing" on their own and could easily be looked upon poorly.

[4][64] Quillen said that the plot "takes some fascinating and truly original turns" and that Nier has "a supporting cast of genuinely interesting folks," and Schilling said that the story made the game "difficult to dislike".

[65] By June 2021, Replicant ver 1.22474487139... had shipped over one million copies worldwide in both physical and digital sales,[75] noted as being double the estimates for the original version.

[77] Famitsu lauded the gameplay improvements and visual upgrade, though one reviewer noted the lack of fast travel and another said some players might be thrown off by "quirks" in the design.

[71] GameSpot's Michael Higham was generally positive about the game, praising its narrative, new elements and music while finding its gameplay and world held back by archaic design.

[72] Mitchell Saltzmann of IGN negatively noted the repetition in later areas and the side quest design, but praised the graphical and gameplay updates along with the new story content.

[73] Julie Muncy of PC Gamer positively noted the improvements to combat and general movement, and praised the story's tone and additions, but highlighted that the original's pacing issues were also retained.

[74] Chris Plante of Polygon enjoyed the slow pace of the narrative and the combat, but disliked the archaic design and was uncomfortable with some of Kainé's storyline.

[79] Malindy Hetfeld of Eurogamer did not like the game as a whole, but enjoyed its later narrative and noted that the graphical and gameplay improvements had made it playable for modern audiences and series fans.

[83] Square Enix executive producer Yosuke Saito later commented that "a number of things" related to Nier were in progress, and that an announcement could be due in 2011.