Space Manbo Mini-Game:
(1) Insert the GBA Cart "Kessakusen! Ganbare Goemon 1+2"
(2) Insert the DS Cart "Ganbare Goemon: Toukai Douchuu Daiedo Tenguri"
(3) Turn the DS power on
(4) Select the Mini-Game option from the Main Menu and choose "Space Manbo"

History Lesson:
(1) Insert the GBA Cart "Kessakusen! Ganbare Goemon 1+2"
(2) Insert the DS Cart "Ganbare Goemon: Toukai Douchuu Daiedo Tenguri"
(3) Turn the DS power on
(4) At certain locations in the game, multiple NPC GBA characters will appear. Go talk to them.