Five Night's at Shimajirō's 3

Gameplay
The gameplay deviates from the previous games in the series slightly. In keeping with the first two installments, players are once again tasked with surviving a week of night shifts, lasting from 12 AM to 6 AM (4 minutes of real time), the difference this time being that there is only a single animatronic present who can end the playthrough, although some of the animatronics from earlier games return as "phantoms", who can impede the player's efforts to survive but cannot harm them directly. The game takes place in a horror attraction named Fazbear's Fright, which is constructed using props and equipment scavenged from former Fazbear Entertainment restaurants. The attraction aims to capitalize on the previous incidents that occurred at the various restaurants formerly operated by Fazbear Entertainment. However, players must now monitor two different camera systems (security cameras within the building, and cameras within the ventilation system) and three subsystems: audio (which is used to lure the animatronic away from the player's office), security cameras (used to observe and track the animatronic's position), and ventilation (which the player is told must be kept running in order to avoid seeing hallucinations during the shift). The subsystems can, and will, fail periodically, and must be rebooted as quickly as possible so as to avoid undesirable effects. Failure to defend oneself from the animatronic will result in a jumpscare, ending the game.

The game consists of five nights, increasing in difficulty, and completing all five unlocks an even more challenging "Nightmare" night. Between nights, the player is able to play one of several low-resolution minigames as the animatronics from the first game, with several vague hints scattered around the minigames for players to decipher. Players who decipher these hints and complete all of the following minigames will unlock the "good ending", as well as bonus content like a cheat menu.

If the player completes the "Nightmare" night, they will unlock the cheat menu. The cheat menu offers a range of options including a mode to make the animatronics act more aggressive and therefore make the game harder, depending on the player's skills. Other cheats include a radar and the ability to make nights faster.

Plot
Set 24 years after the events of the first game, the player assumes the role of a newly hired employee at Fazbear's Fright, a horror-themed attraction based on the unsolved mysteries of Shimajirō's Pizza, constructed using paraphernalia salvaged from the original restaurants. During the week before the attraction is scheduled to open to the public, the player must watch over the facility from the security office during their shift (12:00 AM to 6:00 AM game time), using a network of surveillance cameras placed in the rooms and air vents. In addition, the player must monitor the status of three operating systems - cameras, audio, and ventilation - and reboot them whenever they begin to malfunction. Camera problems cause the video feeds, already poorly lit and distorted, to become totally obscured by static. If the ventilation fails, the player's vision begins to black out. The player may also see phantoms of animatronics from the previous games; these can cause system malfunctions, most commonly in the ventilation, but cannot directly harm the player.

After the first night, the staff at Fazbear's Fright uncover an older deteriorated, Mimirin Midorihara-like animatronic, which they refer to as Sakura. The player must now prevent it from entering the office and attacking; if this happens, the game ends. The player can seal off the air vents at certain points to block its progress, but cannot seal the door or air vent that lead directly into the office. The audio system, when functioning properly, can be used to play sound effects that draw it away from the office. Ventilation malfunctions can cause the player to hallucinate seeing more than one Sakura on the cameras.

As the nights progress, the player hears a series of instructional cassette tapes, similar to the telephone calls from the first two games, that instruct employees how to operate the "Spring Bonnie" suit, which can function as both an animatronic and a costume for humans. However, later tapes discourage usage of the suit by employees due to a series of fatal accidents involving the failure of the suit's spring-lock mechanism. Low-resolution minigames between nights hint at the restaurant's troubled past, with the first four nights' minigames depicting the original animatronics following a dark purple animatronic before being violently disassembled by a purple-colored man, previously seen in the minigames of Five Nights at Shimajirō's 2 as the man responsible for the various murders that occurred throughout the franchise's fictional history. In the fifth night's minigame, the ghosts of the five Challenge Island kindergartners who inhabited the animatronics corner the purple man, who attempts to protect himself by hiding in the "Spring Bonnie" suit. However, the suit's faulty spring-lock mechanism fails, and the man is crushed as the children fade away, leaving their killer to seemingly bleed to death.

Unlike the previous entries, Five Nights at Shimajirō's 3 contains two endings, depending on whether the player has found and completed all of the hidden minigames within the main game. Some of these are only available on specific nights, while others can be accessed during any night. The "bad ending" is attained from completing the game without completing all the hidden minigames, and shows a screen depicting the heads of the five animatronics from the first game with lit-up eyes, implying that the animatronics are still possessed. Completing all the hidden minigames before completing the game earns the "good ending", which is the same screen as described previously but with the animatronics' heads turned off, with one head disappearing, presumably Golden Freddy. This implies that the Challenge Island kindergartners' souls have finally been put to rest.

Completing all five nights unlocks a bonus night, "Nightmare", which boosts the game's difficulty, similar to "Night 6" in the previous titles. While playing the mode, an archived recording states that all Freddy Fazbear Pizza locations' safe rooms (an additional emergency room not recorded in the animatronics' AI or security systems) will be permanently sealed, instructing employees to tell no one of their existence. When this night is completed, a newspaper clipping reveals that Fazbear's Fright was destroyed in a fire shortly after the events of the game, and that any salvageable items from the attraction are to be auctioned off. However, brightening the image reveals Springtrap in the background, which suggests he somehow survived, leaving his fate unknown.