i had played the US version. i have fond memories of it as it was my first SHMUP.
i have a little emulating device called powkiddy v90, its cute and small, i super recommend, it run pc engine games with zero input delay, i played it through a hard time of my life but enjoyed it tremendously.
as for the japanese version, i don't see much difference aside from the narration of power ups and possibly some extra enemies, as i don't remember some of these being in the US version, most people say this is a good game for newcomers of the genre but i could disagree, as it gets quite cheap on some areas, and as you gain power ups your hurtbox gets bigger, making it hard to dodge projectiles without losing your powers