Enter the following codes at the Main Menu:
Debug Information:
Left, L1, L1, Right, R1, R1, Up, Down.
Flycam Option:
Up, L1, Down, R1, R2, Down, L2, Up.
Level Select:
R2, Left, Right, R1, L1, Up, Down, L2.
Invincibility:
L2, Square, L1, Circle, R2, Square, L1, Circle.
Unlock Gallery FMV Sequences:
Circle, L2, Left, R1, R2, Right, L1.
Infinite Musket Ammo:
Square, L1, R1, Up, Circle, L2, R2, Down.
Unlock All Intermission Sequences:
Right, Circle, Square, Square, R1, R2, Left, L2.