Unlockable Character Passwords 
     Enter  the  password  in  the "Recruit" "Password" section of the
main ingame menu.

Password:                Effect:
TTOGZWSREYD              Unlock Arms Magazine Soldier

Unlock special characters. 
     Beat  the different modes on infinity mission to unlock different
characters.

Unlockable:              How to Unlock:
Naked Snake              Beat easy mode in infinity mission. 
Old Snake                Beat Medium mode in infinity mission. 
Raiden                   Beat hard mode in infinity mission. 
Roy Cambell              Beat extreme in infinity mission.