Main Hall Level Path Is a path of levels off from the Ante Room in Beyond Dark Castle, and will show up in Return to Dark Castle. It Consists of 2 Levels, Ante Room, and Black Knight's Showdown & The Final Battle.
The setting of the West Tower takes Prince Duncan through the large gate in the Ante Room, after collection all the mysterious Orbs. It soon becomes quite clear that this is the resting place of the "Final Battle" with the Black Knight.
Main article: Beyond Dark Castle Advanced Ending
This level path ends very differently on Advanced, for more information click the link above this.