After defeating your enemy in the final round, go to beast form (if not beast already) and use your character's beast drive attack (L1 by default or the controller motion given in the manual). After the replays run through, your character's human win pose will be performed in front of the Beast drive attack background (grid walls and floor, black everywhere else).
Complete Arcade mode with all of the characters, then at the character selection screen press start to choose an extra fourth costume.
During a fight, pause the game and hold the R2 button to view the pause at full screen.
After a VS. battle, press L1 to play a rematch.