Notes

The Perfect Ending (Secret Epilogue)
To get this ending, during the interview with Phone Guy, name Old Sport "Jack." After you did that, do the True Ending route (complete Phone Guy's objectives and The Puppet's objectives). When rigging Dave's suit, Phone Guy then will ask you if you experienced the Springlock Failure. Instead of answering him, you can ask if he experienced it himself and he will respond with a story about it. He will say that his name was Peter. (This is not required) After it, attend Friday (Fifth day) and the Saturday Party. In the party, you can choose to call him Peter than Scott. That will result in an extended conversation between Phone Guy and Old Sport. After the extended conversation, DaveTrap escapes and is confronted by Fredbear. You'll play as Fredbear and fight Dave. Remember that attacks won't damage DaveTrap, keep healing until you get The Bite Of 87' ability and use it to kill Dave.

After the fight, you will enter the Happiest Day scene, but with a minor change. The Puppet will only tell your name, It won't say that it's not your real name, nor that you became a body count just like the children.

After the True Ending's screen and a Thank You screen, you'll get a secret cutscene, showing Phone Guy, his wife, his dog and Jack (AKA Old Sport) together in a house, sitting on a couch with Old Sport smiling. After the cutscene, the title screen appears.

(Extra Fact: If this is done after the An End and picking option 1, it may affect the The End cutscene with Shadow Doggo appearing, this time with readable sentences about how he told Fredbear about what you did to him and will mention that he forgives you. If the Pure Evil ending was not completed (you ended it while fighting Fredbear) or you picked the second option, Shadow Doggo will instead mention how glad he is that Old Sport/Jack redeemed himself)