WinBack: Covert Operations cheats and cheat codes for Nintendo 64

Go to the title screen (where you see the "Press Start") and quickly 
press the following buttons. If the codes are accepted, you should 
hear a gunshot.

Unlock Trial mode:
Hit Up, Down, Down, Right, Right, Right, Left, Left, Left, Left, 
then hold C-Down and press Start

One shot kills:
Hit C-Left, C-Right, C-Left, C-Right, C-Up, C-Down, C-Up, C-Down, 
then hold L and press Start

Max power mode:
Hit L, C-Right, C-Left, C-Right, C-Left, C-Down, C-Up, C-Down, 
C-Up, then hold L and press Start 

Unlock all multi-player characters:
Hit Up, Down, Down, Right, Right, Right, Left, Left, Left, Left, 
then hold C-Up and press Start

Unlock all Characters In Multi-Player Mode 
Finish the game in easy and normal mode

Max power, sudden death, trial modes
Finish the game once in hard mode