Enter any of the following keypad combinations at
the Press Start screen:

*To access all levels, type the following keypad 
combination: 
L1, R1, L2, R2, triangle, cross, circle, 
square, square, circle, cross, triangle. 
This cheat code allows you to access all levels when
you get back to the Start Mission screen.

*To access all types of player ships, weapons, and
upgrades, press L1, R1, L2, R2, up, down, right, left,
left, right, down, up