Gunmetal
# A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Mission select
At the mission selection screen, click Left Analog-stick, press Black, R, click Right Analog-stick, White, L.
Mission skip
While playing a mission, click Left Analog-stick, press White(2), Back, click Right Analog-stick, White.
Alternate music
At the front-end, click Left Analog-stick(2), Right Analog-stick(2), press L, R.
Joke mission briefing
At the armoury screen before launching missions 1, 3, 6, 8, 9, or 14, press L(2), R(2), click Left Analog-stick, Right Analog-stick.