Complex sentence: In a reprise of the prologue, where a bratty Jane had demanded ice cream for the two sisters while an audience looked on, Jane becomes "Baby Jane" again and dances for the crowd that has gathered to watch the spectacle.
Split into simpler sentences: In a reprise of the prologue, where a bratty Jane had demanded ice cream for the two sisters while an audience looked on, Jane regresses to her childhood and becomes "Baby Jane" once again. She dances for the crowd that has gathered to watch the spectacle.