By that definition, the US version is indeed difficult in comparison to the JP version.
But really... must we be so damned semantic? The US version is harder, period. That's just how it is. Once you know what do to, of course, it's easy. But that holds true for virtually all difficult games... they get easier as you play them and learn them. That doesn't make them any less difficult on their own. In Exile II, there are parts, especially later in the game, where one wrong step can kill you outright, no matter how much life you have... this is especially true when you're in the Pyramid... walk through the wrong door and fall on a mummy and it's game over no matter how strong you are.