Various cheats
     Go  to  the "Options" menu, then select "Cheats"

Cheat code:                       Effect:
Y, B, A, B, A, X, Y, X            Gives you all of the present day weapons
A,B,B,B,X,Y,B,A                   Unlock Centipede
A,B,B,B,X,Y,A,B                   Unlock Missile Command
A,Y,A,Y,blank,blank,blank,blank   T-850's Fight Hit Points Increased by 50%
B,Y,A,A,blank,blank,blank,blank   T-850's Fight Hit Points Reduced by 50%
B,X,X,X,B,A,Y,A                   T-X Hit Points Increased by 50%
B,B,X,X,X,B,A,Y                   T-X Hit Points Reduced by 50%
A,A,A,X,B,X,B,B                   All future weapons
Y,X,B,B,A,A,B,X                   Invincibility
X,A,Y,Y,Y,A,X,B                   Unlimited ammunition
B,B,B,X,B,A,Y,A                   Unlimited continues
B,B,B,A,X,Y,X,Y                   Unlock all exclusive movie scenes
B,B,B,X,B,Y,B,B                   Unlock all game scenes
X,Y,Y,X,B,A,A,B                   Unlock all levels
X,B,X,A,A,Y,X,X                   T-X endoskeleton in every fight