Fight as Grant:
Highlight Rock at the character selection screen and press Left to highlight Grant. Press any button to select him.

Fight as Kain:
Highlight Terry at the character selection screen and press Right to highlight Kain. Press any button to select him.

Random fighter:
Hold Start at the character selection screen. It is possible to fight as Kain or Grant randomly through this method.

Select victory pose:
Press any attack button immediately after defeating your opponent.

K.O. taunts:
Beat your opponent until he goes down. Quickly press Left + Start, Right + Start, or Right + Down before the "K.O." message appears.