Bronze, Silver, and Gold Passes
"Battle B-Daman 2" provides three levels of cheats, and you must have an appropriate pass to use each level. You automatically start with the Bronze pass. Play through the game, and you will unlock the Silver pass automatically when you are around the halfway point. You must complete the game and make sure that your Game Boy Advance saves after you defeat the last boss to unlock the Gold pass.
To enter codes at any level, go to the "Zero Code" screen. You can access this screen by visiting the parts shop.
Zero Codes: Bronze
To unlock 1,500 B-Daman Bucks, type in "GO YAMATO!" "HEY TOMMI!" and "B-DAFIRING" get you 2,000 and 3,000 B-Daman Bucks, respectively. To unlock Cheesy Mouse, use the code "HARD TEETH." Type "SHOOT IT!!" for the L/R Shield Stand and the Saber Barrel.
Zero Codes: Silver
To unlock Venom Sting, type "VENEMOUS TAIL." "YOKUSAIMARU!," "GUST OF WIND!" and "GOLDEN ARMOR!" get you Yokusaimaru, Oak Raven and Ohryu-Oh, respectively. For Kokuryu-Oh, type "SHADOW ARMOR." "A BLOODY BODY" gets you Blood Shark, and "GLEAMING FANG" gets you Gao Tiger. To unlock the Load Wing Trigger and Saber Loader, enter "TONS OF BALLS."
Zero Codes: Gold
To unlock Blitz Eagle, Revolver Heaven and the Labyrinth, type "THE SWIFT WINGS," "LET'S B-DAFIRE!" and "REVIVAL OF EVIL," respectively. The code "FEROCIOUS WOLF!" unlocks a Storm Chimera and an Assault Beast, and "STRONG RED GALE" unlocks the Chrome Harrier Drive Body. For Stream Pegasus, type "GIFT FROM ATLUS," and for Mega Diabros's DHB Core, use "DEVILISH FIGURE."