Nightmare in Dream Land was the last game to credit Shinichi Shimomura, who co-directed the game with series creator Masahiro Sakurai, as a staff member. Shimomura previously served as a regular map designer for the Kirby series and directed Kirby's Dream Land 2, Kirby's Dream Land 3, and Kirby 64: The Crystal Shards. Exactly what became of Shimomura after Nightmare in Dream Land is unknown, with many fans speculating that he retired from the video game industry and/or passed away.