The biggest impact this has is that the first area of the game might not have been intended to be the ruins of Castlevania at all. I know parts of it look like the classic entry hall motif, but I always thought it was weird that the castle would appear twice in the same game, in different locations with different layouts.
I risk falling into headcanon here, but I think this is explained (implicitly) in the series.
Not only the castle has manifested in different places along the series, but I think it's safe to assume that the ruins of the previous manifestation stay where the castle last appeared. This can be seen in Simon's Quest, where the ruins are at one place (where Simon last defeated Dracula), and in Rondo the castle manifests in another seemingly completelly different place, but still in the same region. Though this doesn't confirm that the ruins of the previous incarnation still exist, it does show that the castle appeared in a different place in relation to Aljiba.
In Aria, Graham Jones confirms that Dracula's Castle exists in Europe but his
true castle exists somewhere else. Genya later reveals that the true castle is a spiritual plane. Couple that with Alucard's explanation of the castle taking "many different incarnations", and I think we could say the castle works by assembling itself from natural matter (stones, earth) so it can exist in the physical plane, but once Dracula is defeated, the true castle returns to the spiritual plane, and the assembled physical manifestation crumbles (like a soul leaving a body, the body dies) causing these ruins to still exist even if the castle appears somewhere else.
In Curse of Darkness, the seal Trevor placed on Dracula's Castle is at the Abandoned Castle. Would not make much sense for him to seal Dracula's Castle in another castle altogether. At least I think it wouldn't.
Also, there's about eight pages at the back of the guide that appear to contain interviews with different staff members, like Iga and Michiru Yamane. I don't know Japanese, so I can't translate them, but I'd be happy to post them here if anyone is interested.
I'm *really* interested. I'm also interested on knowing the japanese name of the areas, mostly because of the Infinite Corridor. You said it's called "Corridor of the Inferno" on the guide, yet I only found the japanese name "無間回廊" for it, which translated to "Infinite Corridor" in one translator, and "Corridor Between Nothing" in another. I want to see how it's written on your guide.