Hamtaro: Rainbow Rescue
# A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
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.
Unlimited Acorns
Press Up, Down(2), Left, Right at the 'Press Start' screen.