This Is What the Witcher 3 Would Look Like if It Were Made in Japan
The program itself is the engine and the necessary set of tools for creating games. Projects such as Yume Nikki, Ao Oni, and others were made on this engine.
Kishi_kun posts a new piece of the game on Reddit once a week. It is unclear whether he plans to recreate the entire Wild Hunt or not. It is also unknown whether this will be a full-fledged demic or whether everything will be limited to the imagination. It looks very cool anyway.