Press X during game play to display the team menu.
Next, hold Select, press Left Analog-stick Up and
rotate it clockwise three times then immediately
rotate it anti-clockwise three times, while continuing
to hold Select. Note: Your selected character will run
around when this is done. While in the same menu, you
should notice that a new icon has appeared under the
log icon in the lower right hand corner of the screen.
Highlight it and press X to display the cheat menu.
The cheat menu allows all weapons, invincibility,
unlimited weapon energy, level skip, and level selection.
First person view:
Repeatedly save and load the same saved game and the view
will eventually switch from third person to first person view.
To go to first person view, press L3. To revert back to
normal, press it again.