Thrill Kill (PSX)

Insant Kill Meter Fill:
At any time during a fight, simultaneoustly press L1 + L2 + R1 + R2 + Square + X + Select

Play as Cain, Judas and Marukka:
Beat the game on the medium difficulty level.

Alternate costumes:
Complete all of a character's moves in practice mode. Then at the character selection screen, highlight a fighter and press L1 + L2.

BellaDonna's third "Thrill Kill": Press Down + Square + Circle + L1.

Have Gimp in practice mode:Complete practice mode with all eleven characters. Gimp will be unlocked at the practice mode character selection screen. Hold L1 + L2 + R1 + R2 and press X on any character at that screen to choose Gimp as your practice opponent.

Fight regular game in practice mode arena:
Complete practice mode with all eleven characters. Then, hold L1 + L2 and press X while any arena is highlighted.