As the player progresses through the game, they discover that Sayori suffers from depression, exhibiting symptoms like forced positivity, overeating, oversleeping, forgetfulness, difficulty getting out of bed, and suicidal thoughts.

[1] Salvato created stock characters based on anime archetypes that were given Japanese names to emphasize a pseudo-Japanese atmosphere.

He wanted to connect more with the characters, and thus explored things like their "insecurities and realistic personality traits" on top of their "stock archetypes".

[3] Due to Salvato's lack of artistic skills at the time, he created the designs of Sayori and other characters in a free anime-creation program, which were used in a test version of the game.

Monika eventually deletes Yuri and Natsuki, revealing that she has an obsessive love for the player as opposed to the character they controlled.

She also reveals that she went into the game's code to modify the parameters of the characters in order to make them less appealing, causing her depression trait to increase.

This version of the game features multiple "side stories" depicting the origin of the club, albeit in an alternate reality where Monika was never self-aware.

In 2018, Sayori was added to Yandere Simulator as a playable character,[6][7] taking the role of an obsessively lovesick schoolgirl nicknamed "Yandere-chan" who seeks to "eliminate" (kill) anyone she believes is attracting her "senpai's" attention.

[13] Fanbyte writer Kara Dennison discussed Sayori's depression, commenting that her aversion to being helped reflected her feeling that it's wasted on her rather than believing she's undeserving of love.

[14] Writer Sky LaRell Anderson, while feeling that the portrayal of her mental illnesses was accurate, begrudged that the game did not take advantage of the interactivity of its medium in depicting them.

[16] IGN Japan writer Shohei Fujita felt that the way the confession and suicide was handled was more ethical than how it could be, suggesting that being able to save Sayori by staying by her side would be objectifying.