This is a hack of the original Rockman (Mega Man) game for the NES, released in Japan. The 'Enk+Small Apple v1.0Beta' hack likely modifies aspects of the original game such as gameplay, levels, or characters.  The 'Rockman Kent' designation suggests a modified name or storyline. Being a ROM hack, the details of its creation are likely from an independent developer in the homebrew scene.

Rockman (Japan) [Hack by Enk+Small Apple v1.0Beta] (~Rockman Kent)

Rockin' Kats (Europe)