Private rank : [Submitted by: Andrew Paul Mills]
At the title screen, press Square, Circle, Triangle, then start a new game.

Sergeant rank : [Submitted by: Andrew Paul Mills]
At the title screen, press Triangle, Circle, Square, then start a new game.

Lieutenant rank : [Submitted by: Andrew Paul Mills]
At the title screen, press R1, L2, L1, R2, then start a new game.

Captain rank : [Submitted by: Andrew Paul Mills]
At the title screen, press Circle, R1, Circle, L1, Triangle, R2, then start a new game.

Major rank : [Submitted by: Andrew Paul Mills]
At the title screen, press L2, Square,R2, Triangle, L1, Circle, R1, then start a new game.

Colonel rank : [Submitted by: Andrew Paul Mills]
At the title screen, press Triangle, Square, Circle, Square, Triangle, Circle, then start a new game.

General rank : [Submitted by: Andrew Paul Mills]
At the title screen, press L1(2), L2(2), R1(2), R2(2), then start a new game.

Master of X-Squad rank : [Submitted by: Andrew Paul Mills]
At the title screen, press Circle(4), Triangle, Square(4), then start a new game

All Weapons With 99 Clips Of Ammo: [Submitted by:SNailB8ter]
Enter at the main Menu: Circle, Circle, Circle, Circle, Triangle, Square, Square, Square, Square.

Unlimited health: [Submitted by:jonus]
Press start and hold L1, R1, press Square, Circle, Circle, Triangle, X, Triangle, Square, Left, Right, Up, X

All weapons: [Submitted by:jonus]
During any mission hold select and start and quickly press X, X, Circle, X, Left, Down, Square.

Start with 10000 points: [Submitted by:Hollow Man]
At start menu press triangle,circle,square.