Unlock Bonus Gallery Picture
Play a character 10 times in any mode to unlock it.
Unlock Character Super Move / Arcana Portrait Art
Each character has a pre-Super Move Animation as well each Arcana has artwork for doing their Arcana Blaze.
All of the Arcana Portraits can be unlocked by doing all 11 Arcana's Arcana Blaze Attacks.
All of the pre-Super Attack animations can be unlocked for doing a super move for each character.
These must be done however in either Story or Arcade mode, because I've tried training mode and none of the accompanied artwork was not unlocked.
Unlock Different Endings
During the fight with Mildred there is two different methods to win in the game's story mode to get two different endings depending on how you win.
Good ending - Defeat Mildred by KO (Knock Out) victory in the Story mode.
Bad ending - Defeat Mildred by Time Out (letting time run out) in the Story mode.
Unlock Story Mode Artwork
For playing story mode for each character in the game you will unlock the character artwork for the story events for the character you picked.
And you will get the character ending art for also beating story mode for the character you chose.