In June 2013 interview with game's designer Toshinobu Kondo published in the Action Gameside magazine, he was asked what meaning there was in the game's title "Sayonara"? He responded:

"That title is a holdover from when we were thinking this would be a final fan service item for the Umihara Kawase series. It had a nice sense of impact so we kept it even as the concept of the game changed. The title conveys a sense of being ready for the end, along with the wish to return."
Contributed by ProtoSnake