The true ending of NeiR Automata was extremely interesting. Players had to complete a nearly impossible bullet hell game during the credits, and after one player actually managed to complete it they were presented with a series of questions ultimately presenting them with the choice to delete all of their data in exchange for the vague promise of saving a complete stranger. If that player persists in their commitment to save someone else, their data was indeed deleted permanently, but the next time someone reached the credits for that ending they were assisted by an NPC representing the player who chose to sacrifice their data. Because of this choice, as time went on, the game got progressively easier as more and more players chose to sacrifice their data to help others.
Pod 153: Pod 153 to player.
Pod 153: Please respond to this query.
Pod 153: Do you, faithful player [Player],
Pod 153: have anything you would like to say to other players
Pod 153: who are suffering because they cannot finish NieR:Automata?
➜ No
➜ To be added.
➜ Yes
Pod 042: Pod 042 to player.
Pod 042: Please respond to this query.
Pod 042: You, [Player], faithful player of this title,
Pod 042: have lost your life multiple times to make it this far.
Pod 042: You have faced crushing hardship, and suffered greatly for it.
Pod 042: Do you have any interest in helping the weak?
➜ No
➜ To be added.
➜ Yes
Pod 042: Selecting this option enables you to save someone somewhere in the world.
Pod 042: However, in exchange, you will lose all of your save data.
Pod 042: Do you still wish to rescue someone—a total stranger—in spite of this?
➜ No
➜ Understood. Returning to title screen.
➜ Yes
Pod 042: The person you save will be selected at random.
Pod 042: As a result, this person…
Pod 042: who cries out for help even as we speak…
Pod 042: may be someone you intensely dislike.
Pod 042: Do you still wish to help?
➜ No
➜ To be added.
➜ Yes
Pod 042: You worked so hard to unlock Debug Mode and Chapter Select…
Pod 042: But they will no longer be available to you.
Pod 042: Do you…still wish to help?
➜ No
➜ To be added.
➜ Yes
Pod 042: You may not receive thanks for your efforts.
Pod 042: Some may say that your efforts are purely for show.
Pod 042: Do you still wish to help?
➜ No
➜ To be added.
➜ Yes
Pod 042: And are you truly—TRULY—sure about this?
➜ No
➜ To be added.
➜ Yes
Pod 042: …Very well.
Pod 042: In exchange for all of your data…
Pod 042: I will convey your will to this world.