* ActingForTwo: Devola and Popola share a voice actress. Jakob and Gideon share a voice actor.
* BilingualDialogue: Invoked at least in Japan. The Japan-exclusive ''Replicant'' version was done with Japanese voices only while ''Gestalt'', the version to be released to international audiences, was done only in English with Japanese text.
* ContinuityNod: Several to ''VideoGame/{{Drakengard}}'', such as the "Red Dragon" that was transported to their world being [[spoiler:Angelus]].
* CreatorKiller: Cavia disbanded a few months after ''Nier'' bombed at retail.
* DuelingGames: ''Nier'' was published by Square Enix at roughly the same time as their post-apocalypse epic fantasy, ''VideoGame/FinalFantasyXIII''.
* TrollingCreator: It's a Cavia game. What do you expect?
* WhatCouldHaveBeen: At one point a PlaystationVita version of the game was in development that would have combined both the ''Replicant'' and ''Gestalt'' versions into a single game, but was cancelled because Square wanted to focus more development time and effort towards ''VideoGame/DragonQuestX''.
* WordOfGay: The creators confirmed that Emil is in love with Nier during interviews. When asked if it might just be platonic, they outright insisted he's gay.
* WordOfGod: According to Yoko Taro, the game's story was inspired by the events of 9/11.
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