At the Starfish logo, quickly press Select, Up, Down, A, Left, Start, then hold Select until the menu above appears. The menu contains a sound test, a (broken) demo viewer, a pause option (enable this, then hold Select and press Start during gameplay to pause, press Select to unpause), an "All Get" option, an invincibility (Muteki) option, and a "Main Only" option.
This needs some investigation. Discuss ideas and findings on the talk page. Specifically: Figure out what enabling "All Get" and "Main Only" do.
