On June 9, 2020, Nippon Ichi Software announced out of the blue that it would be holding three impromptu broadcasts that would act as a teaser for its new game. The three broadcasts occurred at different times on June 10, 2020 and the videos have since been made private.
One broadcast showed off a hamster in its cage, doing things like eating sunflower seeds and running in its wheel. (You can still see the cage for a split second before the thumbnail disappears in a tweet.) The meaning of this is unknown, and fans of NIS are speculating the meaning of the teaser via the hashtag #日本一ソフトウェア新作予想 (NIS New Game Predictions).
Some are speculating that the game might be a new title in the Yomawari horror series, as hamsters are nocturnal and “mawari” means “wandering in circles.” There are also people who are just using the teaser to list out sequels they want, like taking the giant hamster wheel to mean “circle” (“maru”) and using that to predict a new Marl Kingdom game. It should also be mentioned that Nippon Ichi Software has close ties to Hamster, the company behind the Arcade Archives series. They partnered together to publish Arcade Archives titles on the PS4.
Currently, Nippon Ichi Software is working on the action game Shoujo Jigoku no Doku Musume and visual novel Yoru, Tomosu. There’s also Labyrinth of Refrain sequel, Labyrinth of Galleria, which was delayed indefinitely. Until the new game is properly revealed, any predictions should just be treated as nothing more than speculation.