To get the extra costumes for any character, beat the game with that character. For instence if you beat the game with Danzaiver you get his extra costume in the vs mode or the 1 player battle mode.
Extra Costumes and Character's Encyclopedia
Complete Story Mode Using Each Character.
Extra Narrators
Complete 1P Battle Mode Using Each Character.
Play as Boss and Hidden Stage
To play as boss and access the hidden stage, beat the game with 3 different characters in story mode.
Play as Ihadurca
To be able to play as Ihadurca, beat story mode with Setsuna.
Voice Gallery
To gain access to each characters Voice Gallery (and the ability to choose their selection pose) you need to win a certain amount of fights with the required character. Story, 1P Battle and Survival are all OK for this.
Gallery
How to unlock
Alty Al Lazal Poses/VA Gallery
Win 44 matches.
Danzaivar Poses/VA Gallery
Win 42 matches.
Erel Plowse Poses/VA Gallery
Win 49 matches.
Gally 'Vanish' Gregman Poses/VA Gallery
Win 37 matches.
Ihadurca Poses/VA Gallery
Win 84 matches.
Kakurine Poses/VA Gallery
Win 44 matches.
Keiya Tempouin Poses/VA Gallery
Win 60 matches.
Lindwell 'Lie' Rainrix Poses/VA Gallery
Win 60 matches.
Midori Himeno Poses/VA Gallery
Win 50 matches.
Setsuna Saizuki Poses/VA Gallery
Win 46 matches.
Winning Postures and Poses
Each character you beat in story mode will earn you 7 new postures.
Congratulations...