Start a game and enter the main menu. There will be 12 items here, internally numbered 0 through 11 in consecutive order. Whenever you press A to enter a menu and then B to exit the same, it can contribute to entering one of the below cheats. Enter and exit the menus numbered below - which use the game's 0-11 numbering system (0 at the top, 11 at the bottom) - to denote which menus to enter, and then immediately exit. After entering/exiting all the named menus, press Start to apply the code: there should be a sound and message that will also occur. Note that you may advance the game one day by the use of these cheats.

Effect	Code
Enables Mode 1, which allows you to use Controller 2 to instantly win (B Button), lose (A Button), or flee (all else)	8, 5, 2, 0, 5, 10.
Enables Mode 2, which doubles your end-battle score	0, 4, 8, 9, 10, 6, 2.
Enables Mode 4, which is long-range for the main character	0, 9, 5, 9, 10, 9.
Enables Mode 5, which gives an extra battle round to the player-controlled units	4, 5, 6, 7, 7, 7.
Enables Mode 99, which makes the CPU play itself when the player's towns are defeated	3, 3, 6, 11, 11, 7, 0, 8.
Enbables Mode 3, which allows the CPU-controlled units to have an extra round	10, 8, 7, 5, 2, 0.
Max out the mines counter in the current town	1, 1, 1, 1, 1, 1, 1, 1.
Returns you back to the normal battle mode	8, 10, 8, 10.
Skips the battle phase: the battles are all AI-played and you only see the results	9, 11, 9, 11.