This article lists features that were only seen in videos, teaser promotions, and screenshots in the game series but were directly changed or not featured ingame.
Early EndoskeletonSeen from the game's Steam Greenlight and the trailer, Freddy and Bonnie's endoskeleton are very different to their final build. Freddy's endoskeleton from the game's Steam Greenlight icon has triangular teeth and glossy-black eyes possessing red iris instead of white ones. Bonnie's endoskeleton head seen in the trailer looks almost the same.
Mangle with a hookIn the game's third teaser, Mangle is shown to have a hook similar to Foxy. Although ingame, Mangle does not have a hook and instead possesses both hands.
Again in the third teaser, the original Foxy is also seen, with glossy-black eyes and glowing white pupils. However, Foxy is majorly replaced by his pre-rebuilt incarnation Withered Foxy, opposed to his minor minigame appearances.
Unfinished monitor map
In two of the Steam screenshots before the game's release, the Monitor map is unimplemented with vent paths along with both the "Play Audio" and "Map Toggle" button.
Nightmare Foxy's tongueNightmare Foxy's teaser, he is shown to have a long metallic tongue. His tongue was never revealed in-game, aside from his appearance in the main menu screen.
Scott Cawthon reveals in his interview with Dawko that Nightmare Foxy having a tongue makes him look not scary.
Hanging Nightmare MangleFive Nights at Freddy's 4, Nightmare Mangle is shown to be capable of hanging from the ceiling, similar to its original counterpart. It also sports a several amount of hanging strings of wires. However, neither of these are shown in-game.
Multiple BidybabsBidybabs, it seems as though it was originally intended for there to be seven Bidybabs featured. In-game, however, there are only two Bidybabs so far.
Bon-Bon in the ventsBon-Bon is shown crawling through the vents from the first teaser for Sister Location's Custom Night update, but never does so in-game.
Wrong-colored Nightmare Fredbear
In one of the screenshots before the game's official release, Nightmare Fredbear's model has the matching colors to Nightmare Freddy and absolutely no buttons added. This was fixed later on during development.