YandereDev. Since 2014, he regularly publishes test builds for debugging purposes with updates that fix bugs and add elements to the game. There is no official demo yet and the final version is planned to be released in 2019–2022.
In this game, you take the role of Yandere-chan, a jealous Japanese school girl who has decided to eliminate anyone she believes is monopolizing her crush’s attention.
If you’re curious, you may want to visit the official website: