Power Mission is an action game released for the Nintendo Game Boy, with Revision A indicating a later release potentially containing bug fixes or minor gameplay adjustments. It's a side-scrolling shooter where players navigate through various levels, destroying enemies and collecting power-ups.  The specific details of the Japanese version, including its storyline and particular challenges, may differ from other releases.  Power Mission likely features typical side-scrolling shooter gameplay, such as dodging enemy fire and using weaponry to clear stages. Further details on the developer and original release date would require additional research.

Power Mission (Japan) (Rev A)

Populous (Europe)