On the titlescreen you have to hold SELECT when entering Arcade mode. While still holding SELECT, stand on Gore. Press ( holding SELECT ) the following buttons:Cross,Circel,Cross,Circel,3xSquare,4xTriangle,Cross+Circle.
Blood
Repeat the SELECT part as with Bilstein and stand on Bilstein. Press the following buttons: Cross,Square,Cross,Square,Cross,Square, now place the cursor on Kappah, RIGHT,Circle,Triangle,Circle,Triangle,Circle,Triangle,L1+R1.
Kappah
Repeat the previous but stand on Hayato and press the following buttons: Circle, Square,Triangle, Square,Cross,Square,Triangle,Square,Circle,Square, Cross,Triangle.
To play with Kappah you have to have Bilstein first.
Playing in the dark
Hold L2 and R2 down before the fight begins. You can do this after you selected a fighter or between fights. There are 3 hidden fighters you can add to the list.