Samurai Shodown

Note: This game is also titled Samurai Spirits.

Alternate costumes:
Highlight any character in any mode, then press C or Z while selecting them.
Information in this section was contributed by Louie.

Fight as Shiro Tokisada Amakusa:
Wait until the title screen appears, then press Start. Choose "V.S. Mode". Then select either "V.S. Battle" or "Showdown". Amakusa's face icon will be under Tam Tam's and to the right of Senryo Kyoshiro's.
Information in this section was contributed by Louie.

Fight as Wan Fu's Brother:
Highlight Wan Fu and press C or Z while selecting him.
Information in this section was contributed by Louie.

1P vs. Com mode:
Select "Story Mode" (Game Start), then have player two join in. Next, have both players select their characters. When the fight begins, have player two do nothing while player one is attacking. This makes the two player like a 1P vs. Com training mode.
Information in this section was contributed by Louie.

No music during first round:
Select a single player game and wait for the character introductions to disappear. Then, press Start.

Glitch: Gen An's strange appearance:
Enable the BT6T-AAXC Game Genie code. Then, at the character selection screen in Story Mode (Game Start), highlight Amakusa and press Left. You will not see Gen An's face icon, but you will see his sprite.
Information in this section was contributed by Louie.