There's a "Tower of Ruins"/"Castle Treasury" stage, a "Soldier's Quarters"/"Barracks", and there's now an "Inner Wall" as well as an "Outer Wall".
And I haven't touched a lot of the Underground yet either.
The plan is:
-Underground Gardens (Nocturne in the Moonlight - SegaSaturn)
-Abandoned Mine (Symphony of the Night)
-Catacombs (Symphony of the Night)
-Heart of the Castle (the cube where one would fight Dracula - SotN & HoD)
Areas that need to be finished up or connected:
-Top of the Inner Wall (resembles SotN's 'Outer Wall')
-Clock Tower (gearworks)
Secret Passages to/from different areas in case you want to re-explore.