Masahiro Sakurai’s latest video in his educational and informative book Masahiro Sakurai on Game Creation is here and well worth a watch. One of the tidbits of information Sakurai provided in the latest video is that he informs viewers that back in July 2021, while he was busy working on the successful Super Smash Bros. Ultimate DLC, said that he “received a request to write a game proposal, which I completed at lightning speed.”
“I’m sorry I can’t share more about this project, but assuming we can get it done, it should be released sooner or later.”
Elaborating a little further, Sakurai adds that his commitments to Super Smash Bros. Ultimate ended in October 2021, at which point he was “given the OK to move forward with production” of the mystery game, although “it was going to take some time to get the right team together.” He reveals that “the target timeframe was April 2022,” but until that point “it will have to wait.”
