NieR Automata was one of last year's surprise hits, exceeding sales expectations thanks to its polished character action gameplay and story which evolves over multiple playthroughs. However, for all the evolving branching narrative players have discovered, there's something unpleasant apparently still hidden for players to potentially find.
Revealed in a one year anniversary interview in Weekly Famitsu, and translated by Gematsu, developers say there's still a secret left in the game for players to find, but due to its unpleasant nature, the creators will not be telling anyone how to find it.
“That” has yet to be discovered. It will definitely be unpleasant, so the developers will not officially announce what it is. For various reasons, this specification was put into the game. If they are more detailed about what it is, problems might occur, so they cannot say anything more. It is the final secret of NieR: Automata…
While it's currently unclear what this particular secret is, we did learn a couple of other secret tidbits from the interview, like that holding a D-Pad direction and hitting R3 will change the camera zoom, but might also cause the camera to clip through textures. Considering a camera control prompt was hidden from players, it certainly sounds plausible that something bigger is still hidden and waiting to be found.