All missions
Press X, L2, Triangle, R2, Select at the title screen to 
unlock all missions.


All special features
Press L1, L2, R1, R2, X, Select at the title screen to 
unlock all specials features.


Invincibility
Begin a mission, then pause game play. Press L1, R2, L2, 
R1, Select to become invincible.

All guns
At the main menu, hit x, left, triangle, square, x, select.