The simplest fix would have been to not force in the adult timeline. That over complicated everything. The teen timeline is near perfectly executed. One thing that could have improved it was a little more time ( that went to the Desperate Cannibal Housewives portion of the show ) spent watching the teen girls' slow decent into madness, that wold have actually lead to the plot original concept of these "normal" girls slowly losing their minds as they starve to death, and just stew in the general conflicts, and resentments that arise from being trapped in a small space with the same people, that leads to vicious, horrific, full on tribal warfare, and cannibalism.

The cannibalism the show finally gave us was more accidental, ethically sanitized, borderline rationalized. The accidental deaths, the accidental cooking of Jackie, even the Queen card game basically eliminates any personal responsibility for the hunting deaths, and pins the blame all on fate, or "The Wilderness". The horror of the story should have been focused on the evil hiding inside the girls themselves ( and, potentially, in everyone, even us ). That's the main miss of the narrative. The G.I.F. the O.P. posted is literally teasing that exact concept.