# Gnosia

Gnosia is a 2019 visual novel social deduction role-playing game developed by Petit Depotto. It was originally released in June 2019 for the PlayStation Vita, and was ported to the Nintendo Switch in December 2020, with a Windows version released in January 2022. It also released for PlayStation 4, PlayStation 5, Xbox One and Xbox Series X/S in December 2023. An anime television series adaptation produced by Domerica is set to premiere in October 2025.

## Gameplay

This game uses a visual novel role-playing game format mixed with an RNG social deduction game. It is single player and utilizes a timeloop structure to create new situations. Aboard a spaceship, the player and several NPCs must deduce who on board is a Gnosia, an alien-like creature that will kill the regular humans on board. The player works with the NPCs to suss out and nominate the potential Gnosia suspects and put them into cryo-sleep. The player can also be Gnosia, in which case they know the other Gnosia on board and will work together to try to eliminate the humans. The number of Gnosia as well as the number of NPCs on board as well as the player's role, is determined prior to each loop beginning. In addition to regular humans and Gnosia, there are other roles, including the Doctor (who can investigate the recently frozen NPCs and determine if they were human or not), the Engineer (who can investigate non-frozen characters to determine if they are human), the Guardian Angel (who can protect high-risk targets from elimination by the Gnosia), and the Bug (who is essentially playing for themselves, trying to stay alive to the end of the round and seizing victory for themselves, destroying the universe).
Throughout playing these loops the player will encounter many events with the other characters, which provides additional backstory to them as well as the universe they are in. In order to get to the ending of the game, the player must encounter all of these events first, many of which are locked behind a specific set of parameters for each loop. The game allows for an "event search" function on the ruleset screen, which lets you make it more likely to run into the events triggering.

## Plot

Gnosia is set in the far future, where humanity has become a massive spacefaring civilization, dealing with a threat called Gnosia, an infestation that compels people to murder other people in the name of their god, Gnos. The player character manages to get a ride on a refugee ship escaping from a planet being ravaged by the Gnosia. However, during the trip to another planet, the ship's computer LeVi detects Gnosia infection on board the ship and following protocol, instructs the passengers and crew to deduce which one of them is the Gnosia and put them into cold sleep. If they fail to do so, the ship is forced to self destruct. However, the player quickly discovers that regardless of the outcome of the investigation, time loops back to the initial discovery of the Gnosia infection. The player also discovers one of the passengers, Setsu, has also been trapped in a series of time loops, and they both agree to collaborate to figure out to escape their loops. However, when time loops, the conditions are not always identical; the number of humans and Gnosia can change, as well as the identity of the Gnosia. The player even gains the ability to manually adjust the settings for each loop as they play through numerous different scenarios.
The cast consists of 15 different characters, with the initial loop involving the player, Setsu, Raqio, SQ, and Gina. Other characters join in future loops, including Stella, Comet, Chipie, Sha-Ming, Jonas, Kukrushka, Yuriko, Otome, Remnan, and Shigemichi. The player learns from the shrine maiden Yuriko that Gnos is actually a collective hivemind of "cyberised" humans who uploaded their minds to an electronic database and use the Gnosia as a means to add more minds to their collective. Yuriko also points out that the player themselves are an anomaly, since the ship only finds out the Gnosia infection since the player is supposed to be the Gnosia's first victim, meaning the player has been looping to timelines where they have already died. Raqio also eventually reveals that the player and Setsu's time loops are caused by an entity called the "Silver Key", which attach themselves to humans and gather data through the time loops they experience. Once the Silver Key collects enough information, it leaves to a different universe to continue its life cycle.
After enough loops and unique scenarios, the player will finally gather enough data to fill up their Silver Key, looping to a timeline where nobody on the ship was infected by the Gnosia. The player's Silver Key then opens a portal, and in order to prevent a time paradox, Setsu decides to take that loop's still hibernating version of the player character through the portal, with Setsu staying in the loop because their Silver Key has not been filled yet. The player is forced to part ways with Setsu and returns to the rest of the passengers and crew, who celebrate having escaped the Gnosia Plague but have completely forgotten Setsu's existence.
In the game's true ending, the player decides to follow Setsu to the other universe by starting a new game file. Setsu is shocked, but welcomes the player's help, as Setsu's Silver Key has now filled up thanks to the player's arrival, meaning Setsu's time loop can be closed now as well. Setsu uses knowledge gained from other time loops to discover the identity of the Gnosia, Manan, who is in SQ's body and is only conscious when SQ is the Gnosia. Wanting to avoid putting anyone in cold sleep or having anyone die, they take advantage Manan's desire for immortality by tempting her with the Silver Key, which she could use to loop forever. They give her access to a robot body known to be Kukrushka by the player and Setsu, and have her take the Silver Key through the portal into another universe. Having broken free from their respective time loops, the player and Setsu finally take a moment to relax together without having to worry about the future.

## Development

Gnosia's development first began in 2015 by four-person indie studio Petit Depotto, being their second video game released after Unholy Heights. Unholy Heights originally released in Japan on the Xbox 360 in 2012. The Gnosia team was led by game designer Toru Kawakatsu, who goes by the pseudonym Mezukare. They were inspired to make the game after playing a werewolf-style game and finding the construction of the experience lacking, which lead to them planning to make their own version they would enjoy. Development of this project began in 2015 on PlayStation Mobile, though it was initially not planned to be released. It was eventually announced for a PlayStation Vita release in 2017, and was ultimately published by Mebius in Japan on June 20, 2019, shortly after the platform was discontinued. The music was composed early into development, without the context of the gameplay, cast, or story to develop it.
Unlike typical werewolf games, which are multiplayer, Gnosia was always designed to be a single-player narrative-driven social deduction game. Mezukare noted that the kind of game they were making was unusual, so they had to take it "one step at a time" while writing the story, with the process taking a long time to do. The team received advice from Amphibian, the designer behind a similar game called Raging Loop, which helped the process along. The loops were designed in order to last anywhere from 5-15 minutes in length. The first 15 loops of the game were intended to serve as the game's tutorial. In this part, the discussions were simpler, and characters and roles were introduced gradually. Despite being exclusive to a discontinued platform and having an initially slow week, Japanese critics enjoyed the game. This, in conjunction with them being an unknown developer and it having little competition, lead to increased attention and sales. The sudden support was a happy thing for the team, with Mezukare stating that it gave the team confidence.
It was designed as a Vita experience, with the logic of being on the Vita being that it would have been "buried" on other platforms by the competition. This logic was the same for why Unholy Heights released on the Xbox 360 despite being unpopular in Japan and late in its life, adding that having a small userbase typically leads to better reviews and the ability to target would-be fans more directly. By comparison, he noted, a bigger platform may lead to people who are not their target reviewing their games negatively. The popularity of Gnosia lead to people requesting they release a Nintendo Switch port of the game. They were not considering a port at first, though they were swayed when they noticed a number of commenters saying that the Vita was "dead." They were also recognized by Nintendo, and given a 70-second spot on a Nintendo Direct presentation advertising Gnosia for the Nintendo Switch. Hideki Yasuda, an Ace Research Institute analyst, believed that it would not have gotten this attention if it launched on Vita and Switch at the same time.
Petit Depotto self-published the game for the Switch on December 17, 2020. It ultimately released internationally on the Switch on March 4, 2021, published by Playism. A Windows version was released on January 23, 2022 in English, Japanese, and Chinese, following a delay from 2021. A port to PlayStation 4, PlayStation 5, Xbox One and Xbox Series X/S was released worldwide by Playism on December 14, 2023.

## Reception

Aggregate score :
| Aggregator | Score |
| Metacritic | 82/100 |
Review scores :
| Publication | Score |
| Destructoid | 7/10 |
| Electronic Gaming Monthly | 4/5 |
| Famitsu | 36/40 |
| GameSpot | 8/10 |
| IGN | 10/10 |
| Nintendo Life | 8/10 |
| Nintendo World Report | 8/10 |
Gnosia received generally positive reviews from video game critics, recognized as the best indie game of 2019 by Famitsu. Katsuhiko Hayashi, head of the Famitsu Dengeki Game Awards committee, awarded Gnosia due to the "level of satisfaction we heard from players [being] extremely high." In 2022's Famitsu Dengeki Game Awards, Gnosia was voted number one in every category, including best indie game, most unique indie game, best indie game music, best indie game scenario, and best indie game character. The latter category was won by Setsu, though the second, third, and fourth placements were held by Raqio, Sha-Ming, and SQ, respectively. It received a score of 82 on MetaCritic based on 39 reviews, ranging from a perfect 100 from Digitally Downloaded to a 40% from Switch Brasil. Mollie Patterson of Electronic Gaming Monthly praised the game's single-player adaptation of a typically multiplayer affair, stating: "arguing against the computer in an attempt to determine who is the human-killing alien in your group is far more dynamic and exciting than you’d ever expect this type of game to be." Nintendo Life's Trent Cannon found joy in the "clever, varied game design," deeming it perfect for both short or long gaming sessions.
Heidi Kemps of GameSpot offered both compliments and criticisms, lauding Gnosia's "intriguing story that slowly reveals its truths, keeping you interested in coming back for more," while lamenting the lack of character dialogue during discussions. Heather Johnson Yu of HeyPoorPlayer echoed Kemps' sentiments, both negative and positive, with a glowing addition that Gnosia was "my contender for GOTY 2021." The limited dialogue options were a dealbreaker for Igor Rangel of Switch Brasil, who considered the immersion "shallow" and suggested voice acting to offset the response issues.

## Anime adaptation

An anime television series adaptation was announced on December 1, 2024. The series is produced by Domerica and directed by Kazuya Ichikawa, with Jukki Hanada handling series composition, Arisa Matsuura designing the characters based on Kotori's original character designs, and Hideyuki Fukasawa composing the music. It is set to premiere in October 2025.