Unlock Everything:
     At  the  mission select screen press Left Analog Stick, Black, R,
Right Analog Stick, White, L

Finish Current Mission:
     During  gameplay  press  Left  Analog Stick, White, White, Black,
Right Analog Stick, White

Change Front-end Music:
     Go  to  the  Front  End  and press Left Analog stick, Left Analog
stick, Right Analog stick, Right Analog stick, L, R

Spoof Mission Briefing:
     Go to the armory screen just before launching a mission and press
L,  L,  R,  R,  Left  Analog-stick,  Right Analog-stick. Only works on
missions 1, 3, 6, 8, 9 or 14