Unlock CO Kanbei
Complete the Normal Campaign and you can buy Kanbei at the Battle Maps screen.
In-game reset
Press Start + Select + B + A during game play.
Deleted saved games
Hold L + Right + Select when turning on the Game Boy Advance.
Advance campaign mode
Successfully complete campaign mode. Enter the battle maps screen and buy the "Advance Campaign" item for one coin. Hold Select and select campaign mode to begin and advanced campaign, with a more difficult CPU opponent. Note: This also unlocks Olaf as a CO.
Field Training bonuses
Successfully complete field training mode to unlock the "War Room", "Campaign", "Design Maps", "Stats", and "Special Intel" options.
Skip Field Training
To skip field training and get to the main part of the game just complete the last mission, 'Fog of War' in Field Training.
Unlock CO Grit
On Mission 4 in campaign mode, choose Max and then you can buy Grit for 50 coins at the Battle Maps shop.
Unlock CO Sturm
Unlock Grit, Eagle, Drake, Kanbei, and Sonja. Sturm can be bought for 100 coins at the Battle Maps screen.
Note: Sturm's profile in unknown but after some testing I found his strong bonus is that in clear weather, all terrain has the cost of 1 and his CO power is a meteor that injures all units it touches.
Unlock CO Sonja
First, get an "A" rank or better in Kanbei Arrives, Mighty Kanbei and Kanbei's Error in the campaign mode to unlock the bonus Sonja missions. Win the bonus Sonja missions in campaign mode. Sonja can be bought for 60 coins at the Battle Maps screen after the campaign is over.
Unlock CO Nell
Get an "S" rank in advance campaign and war room modes. Nell can now be bought at the Battle Maps screen.
Unlock CO Eagle
Use Sami to win the Captain Drake, Naval Clash, Wings Of Victory, and Battle Mystery missions in campaign mode. Then, win the Rivals battle. Eagle can be bought for 80 coins at the Battle Maps screen after the battle is over.
Unlock CO Drake
Use Andy to win the Captain Drake, Naval Clash, Wings Of Victory, and Battle Mystery missions in campaign mode. Drake can be bought for 50 coins at the Battle Maps screen after the campaign is over.
Note: To buy Kanbei you need 50 coins.
Stop Unit Production
To stop the CP producing a unit at a base/port or air port just put one of you units on the square where the base is.
Gold Options
To turn certain options at the selection screens gold and flashing you must complete these things.
Option - Task
War Room - Get S rank in all 20 maps
Campaign - Complete Advance Campaign
Battle Maps - Buy everything that you can get
Records - Get Rank 1 on your badge and complete all War Room maps
Field Training - Get 14 As in Field Training.
Special Intel
After you have finished the Field Training missions (and in the course opened up the War Room, Campaign, Design Maps and Stats features), go back into Field Training. A very short tutorial called Special Intel is now available that gives you extra gameplay tips.
Have War Room Flash Gold
Win all levels with a special rank and a score above 500 points.