Ghosts 'n Goblins (Makai Mura)

[Protoman]

This game... I like it but will never beat it. I've gotten to the last stage twice but can't get up to the boss because there are two goblins per level going up after the dragon, and they take 10 hits each, walk slowly toward me while eating hits and kill me before I kill them, the red areemer nearby don't help either.
However 99% of playthroughs found on Youtube only have 1 goblin per level. And I've played TWO different versions of the game, the Capcom collection PS1 port and the WII VC port. I was flabbergasted, but a trip to the Cutting Room Floor reveals what should have been obvious to me, the arcade game has several revisions. The revision notes doesn't count the goblin problem, but it does mention the two unicorn boss monsters after the first ladder as well as the boss being two satans, something I have not seen in my versions. Still, facing two unicorns(which you can't beat feasibly, you have to jump into one, sacrifice your armor and get bounced up, the armor you can get back after the dragon anyway), still seems easier than having two goblins to face, because while I have no idea how these LPers can seem to shoot so many shots off in a second, I can not. The fastest way of shooting is to tap a direction while shooting, but that of course has me walking toward the enemy so if there are two of them that means I need to get out 20 shots super quickly which even with that mehod does not work.
ANYWAY, TLDR aside, that's not even what I want to ask anyone about!

My question is simply this:WHAT DOES THE DIFFICULTY SELECTION DO? Easy - Normal - Expert. I have tried "easy" and normal but I can't tell any difference whatsoever. Does anyone know?