Unlock Hard Mode
Highlight the "New Game" option at the main menu. Then, hold Square + Circle + L1 + R2 + Select + Up + X.
Unlock Super Agent Mode
Pause game play and highlight the "Weaponry" option. Then hold Right + L2 + R2 + Circle + Square + X. A sound will confirm correct code entry. Enter the options screen and select "Cheats".
End Level Successfully
Pause game play and highlight the "Map" option. Then hold Right + L2 + R2 + Circle + Square + X. A sound will confirm correct code entry. Enter the options screen and select "Cheats". This allows the current mission to be successfully completed.
