Gekitou Power Modeller, a Japanese release for the Game Boy, is likely a fighting or action game given the title. "Gekitou" translates to intense battle, while "Power Modeller" might refer to character customization or building features.   Without more information, specifics regarding gameplay are limited.  Further investigation of Japanese gaming databases would be needed to confirm the developer, release date, and gameplay features.  The title suggests a focus on fast-paced combat and potentially some degree of character design or customization.

Gekitou Power Modeller (Japan)

GBKiss Mini Games (Japan)