Some questions about Castlevania Portrait of Ruin (CONTAINS SPOILERS)

[Spindel]

Ok so I know this isn't a new game or anything like that but I thought I might ask some questions here anyway since I picked the game up not long ago.

FROM THIS POINT ON THE POST CONTAINS SPOILERS!!!!

My gripe with the game is that I have come so far that I defeat Stella and Loretta, Bruaner comes and takes them away the castle starts to rumble and is destroyed and the game ends.
My issue starts here: The game just ends, WTF??
It's probably one of the worst endings in a game since playing Duck Hunt on the NES.

Is there an alternative ending to that ending I got?
Does it involve me having to finish all of Erics quests? (some of them I can't finish since I found items and sold them before knowing there was a quest for them)
Or is the end just like that, absolutely nothing that ties the loose ends of the story together?

I just have a feeling that I'm supposed to be able to get to the other side of the barrier at the throne room in some way.
I also see on the map that in the room where you meet Loretta and Stella there is supposed to be a opening on the left hand side, but that opening isn't there while fighting against the two girls.