Chronicles Original Mode is different in many ways to the Arranged Mode, including that in order to see the true ending you have to do like 11 loops, and then Simon Belmont appears smoking in a kind of bizarre drawing.
I never did that. But I'm aware of its existence.
However, if all you have to do is beat it once, then Haunted Castle is way harder, because I could only do that using save states emulating it, while I did beat Chronicles Original Mode. Not without trouble, but I did it.
And that's why I voted for Haunted Castle.