Hamtaro: Rainbow Rescue Cheats - GBA
Primary Collection of Cheats
Unlimited Acorns
Press [Up], [Down], [Down], [Left], [Right] at the "Press Start" screen.
Secret Coloring Picture at the Clubhouse
Stand in front of the blackboard in the Clubhouse and press the [A] button. After reading the message, press the [L], [R], [A], [B] buttons in this order and you'll receive a secret coloring picture.