The series presents new information that had not been widely publicized before, including a pivotal tip that was overlooked for years which eventually leads to an arrest. It also links the killer to more homicides spanning two decades, providing a more detailed and updated investigation than previous documentaries on the case.

Gone Girls: The Long Island Serial Killer centers the victims and their families in the narrative, giving viewers a fuller picture of the horrors inflicted by the killer. It highlights the resilience of the victims' families and the injustice and corruption surrounding the investigation, rather than focusing primarily on the perpetrator.

The series shows how the police and authorities failed the victims and their families spectacularly, with the investigation going unsolved and uninvestigated for nearly 20 years. It reveals how a pivotal tip was overlooked for years and how systemic issues contributed to the delay in solving the case.

The first episode is factual and procedural, focusing on the initial disappearance of Shannan Gilbert and the discovery of multiple bodies. Subsequent episodes introduce more characters, police officials, and media coverage, with the third episode considered the best by some viewers for its depth. The final episode is somewhat ambiguous, reflecting the unresolved nature of some aspects of the case.

Yes, the series links the killer to more homicides spanning two decades, suggesting a broader scope of crimes than previously known. It implies that Rex Heuermann, the arrested suspect, may have gotten away with many crimes, indicating the possibility of additional victims beyond those initially discovered.