At the Main Menu, press and hold R1 + L1 + R2 + L2 (hold for about 3 secs). The secret cheats screen should appear. Below is a list of all the avaiable cheat codes.
To enter a code, simply hold X, then scroll left or right on the d-pad untill you reach the desired letter...to move to the next letter, let go of X.
***NOTE: Once you have enter EACH code, make sure you press SQUARE, to activate the cheat.
"DEMONISE" - Invulnerability (Makes Jen/Scree invincible to enemy attacks).
"MORTIFIC" - Easy kill (Enemies are killed by one hit).
"SNOWFLIGHT" - Opens the scene selection option up to the end of Solum.
"CHARYBDIS" - Opens the scene selection option up to the end of Aquis.
"FLINTLOCK" - Opens the scene selection option up to the end of Aetha.
"SUNSTONE" - Opens the scene selection option up to the end of Volca (end of the game).
"ARCANUM" - Opens all images in the Tarot Card gallery (as though all cards have been collected).
"SEABREEZE" - Opens 'Actors Featurette' video.
"AURORA" - Opens 'Making Of...' video.
"PSYCHOSIS" - Opens '16Volt Interview' video.
"MIRRORY" - Opens all bonus video's, including 'Trailer' video.
"ASCENDANT" - Opens all bonus video's including 'Coming Soon...' video.