Highlight Shingen at the character selection screen, then quickly press X(5x), B(10x), X(2x).
EX Mode
At the Character Selection screen, select Speed and press X(6x), Left, B, B, B, Right, X, X, X, X.
Hanafuda Card Game
To unlock the hidden Hanafuda Card mini-game, beat Last Blade with any character without using any continues. You will find the Hanafuda option at the main menu screen.
Mirror Matches
At the Character Selection screen, highlight Akari and press X(8x), B(9x).
Play as Kouryu
At the Character Selection screen, highlight Kaede and press X(10x), B, B, B, B, B, X, X, X, X.
Play as Original Kaede
At the Character Selection screen, highlight Kaede and press X(9x), B, X.