Adult text adventure doujin game originally released in 2022, developped by HUNGRYCULT (previously known as "122pxsheol, Hankei 122px no Meido, Seiniku Jousai / 半径122pxの冥土、精肉城砦"). Re-released with official English, Korean and Chinese translations on Steam on 09/18/24. A sequel called HAPPY SAIN† ZERO is in the works, along with a spin-off, HAPPY SAIN† SHEOL ~Mouja Shoujo Maya~.
