Note: Amakusa can only be played at Vs. and Count Down modes.
Play as Extra Characters (Game Boy/Super Game Boy)
In the intro, when you see Haohmaru hanging the sword and cutting the objects at your side, rapidly, press 3 times, you should hear a chime after you do this code, because the code is one of the most harder to work, if you do these steps, at the character selection screen, Kuroko, Hikyaku, and Amakusa will appear below the 12 normal characters.
Play as Galford's Dog Poppy (Xbox, PS2)
At the character select screen, hold down start and choose Galford.