To access the game's secret mode, plug in both controllers. Pause the game and hold down buttons A and B on controller 1, and button C on controller 2.
Once this code has been registered, you can go to the next battle, war or get maximum medics as follows.
To execute battle advance, hold down buttons a, c and press up on controller 1, and button b on controller 2.
To execute war advance, hold down buttons a, c and press down on controller 1 and press the b button on controller 2.
To get Maximum Medics, press buttons a and c on controller 1 and button b on controller 2.
Contributed By: BanjoKazooie.
After you have your units to attack, pause the game. Any weapons in the air (i.e. rocket, grenade, TNT) will continue to move while the men on the field remain frozen. Any weapons that hit will damage and possibly kill their targets while the game is still paused.
Contributed By: GForce9x.