Three years and ten months after release, someone finally found Nier: Automata's final secret. It was announced by discoverer Lance McDonald, then confirmed by series director Yoko Taro less than seven hours later. The confirmation of the final secret was also noted by the official Nier account. Spoilers follow, but frankly you'd literally have to delve into the game's code to discover this. Here's Yoko Taro's tweet, with McDonald's tweet embedded:
( NieR:Automata Spoilers )........3 years 10 months.（◎血◎）RT: @manfightdragonI found a cheat code in NieR Automata (snip) https://t.co/2LeNlBguLiJanuary 3, 2021
The final secret was a cheat code performed after killing the first boss. It's a complex series of attacks, rolls, and moves in the vein of classic cheats that must be done while standing in a specific spot. Once performed, the player is instantly transported to the "last" of the endings, of which the game has many, a decision that deletes the user's save and unlocks bonus game modes. To be clear, it's not an exploit, it's a cheat deliberately programmed into the game. Asked how he found it, Lance McDonald replied, "hundreds of hours of reverse engineering."
Nier: Automata was a sleeper hit when it released, surprising both critics and series fans with its widespread popularity and complex narrative tricks. For more on its narrative legacy, go over and read about how Nier: Automata's study of human frailty overpowers its own flaws.