Osana Najimi originally had a very different design. Originally, she had yellow eyes, short strawberry blonde hair tied into two ponytails, and two pink and white spotted bows holding up her ponytails. However, her appearance changed radically changed to her having orange eyes, two very long orange hair tied into two very long ponytails that reach to her knees, and pink rubber bands holding up her ponytails. The change in appearance was made due to YandereDev thinking that she didn't look "Tsundere" enough.
Although the developers and voice actors come from several different places in the USA, most of the development takes place in California.
Ayano's voice actor, along with Senpai and Budo's voice actors, has suspended their participation as voice actors for Yandere Simulator in response to the grooming allegations the game's developer YandereDev faced.
Concept art of Yan-chan fighting Info-chan on the school rooftop surfaced, heavily implying Info-chan was the game's final boss and leading to speculation that she was also the second Yandere. In September 2015, YandereDev confirmed both rumors, alongside an announcement that the idea had been scrapped.
When asked by fans why certain non-core game elements appeared when they did, YandereDev has admitted outright that almost every case was him trying something just to test if he could do it.