As in Five Nights at Freddy's 2, when a game ends, the player may be given a chance to play an 8-bit minigame, in which Circus Baby must give cupcakes to children and then bring an ice cream cone to a little girl. Completing this minigame grants access to a secret level during Night 5, a near-recreation of the gameplay in the original Five Nights at Freddy's. Here, the player remains in a security office and must prevent a hybrid animatronic called "Ennard" from entering it by watching surveillance cameras and closing electric doors, all of which consume a limited power supply.
Clearing all five nights unlocks a gallery of extra features: pictures and blueprints of the game's animatronics, their making-of, a map of the facility, and automatic access to Circus Baby's cupcake minigame. As of the 1 December 2016 update, clearing all nights also unlocks the non-canon Custom Night mode, which is set in a modified version of the Night 5 secret room. The player can choose from several modes and difficulty settings, facing new animatronics, and must conserve both power and oxygen supplies in order to survive. Completing these modes allows the player to view a series of cutscenes that have been declared as part of the series canon; all except the last scene are in 8-bit resolution.
An achievement system exists in the form of four stars, obtained by unlocking both of the game's endings, completing the Circus Baby minigame, and completing the hardest difficulty on each custom night preset.
Like in all Five Nights at Freddy's games, failure to defend oneself from the hostile animatronic characters will result in a jumpscare, ending the game.