PC CHEATS
Create a shortcut on your desktop, then right click on it and go into 'Properties'. Into 'Target' add -cheat at the end of the command line then confirm. Launch the game with this shortcut, then during your gameplay do a right click to display the action menu then click on the exclamation mark to the bottom right to access the cheats.
PS2 CHEATS
During the gameplay press X to display the Options menu. Now hold SELECT while rotating the LEFT STICK clockwise three times, beginning from left. Then, click on the small icon at the lower right corner of the resource menu.