For infinite ammunition, pause the game at any time and insert the following button combination: R2, R1, Triangle, Square, Right, Down, Left, L1, L2, R2, R1, Triangle, Square, Right, Down, Left, L1, L2, R2, L2, L1, R1, Triangle, Left, Down, Square, R1 & L1 (simultaneously). If done right, a sound will confirm correct entry. This code can only be used on easy mode and story mode, and must be re-entered as you traverse different stage (or if the game is shut off).
For infinite health, pause the game at any time and insert the following button combination: Down, Down, Down, Up, Triangle, Up, Triangle, Up, Triangle, Up, Up, Up, Down, Square, Down, Square, Down, Square, Left, Triangle, Right, Square, Left, Triangle, Right, Square, R1 & L1 (simultaneously). If done right, a sound will confirm correct entry. This code can only be used on easy mode and story mode, and must be re-entered as you traverse different stage (or if the game is shut off).
To add 500 Thermal Energy Points automatically, pause the game at any time and insert the following button combination: Up, Up, Down, Down, Left, Right, Left, Right, Square, Triangle, R1 & L1 (simultaneously). If done right, a sound will confirm correct entry. This code can only be used on easy mode and story mode, and must be re-entered as you traverse different stage (or if the game is shut off).
To unlock Extreme Difficulty, beat the game once through on normal difficulty.