  Interactive digital stories provide a sense of flexibility and freedom to
players by allowing them to make choices at key junctions. These choices
advance the narrative and determine, to some degree, how the story evolves for
that player. As shown in prior work, the ability to control or participate in
the construction of the narrative can give the player a high level of agency
that results in a stronger sense of immersion in the narrative experience. To
support the design of this type of interactive storytelling, our system,
EntangleVR++, borrows the idea of entanglement from quantum computing. Our use
of entanglement allows creators and storytellers control over which sequences
of story events take place in correlation with each other, initiated by the
choices a player makes. In this work, we evaluated how well our idea of
entanglement enables creators to easily and quickly design interactive VR
narratives. We asked 16 participants to use our system and based on user
interviews, analyses of screen recordings, and questionnaire feedback, we
extracted four themes. From these themes and the study overall, we derived four
authoring strategies for tool designers interested in the design of future
visual interface for interactively creating virtual scenes that include
relational objects and multiple outcomes driven by player interactions.
