This is a "Visual Novel". There is a NES game with the same title, but it is a completely different type of game.
The FM-7 version manual offers more extensive information presented by the development staffs. https://www.youtube.com/watch?v=_1zkJUJRExM&ab_channel=petsasjim1
English translation of the FM-7/PC-8801/PC-9801 version manual: https://gamefaqs.gamespot.com/msx/952974-gall-force-sousei-no-jokyoku/faqs/76942