The second half of Hunters in the Snow includes some surprising twists and turns. How are these more meaningful and substantial than the random...

The twists in the story are more meaningful and substantial because Wolff is making a parody of the beliefs held by American Romantic writers (think of Thoreau and Whitman) who believed several key ideas: cities are vile and corrupt, the wilderness is a place of natural beauty and a place where one can gain a higher sense of truth, women are to be distrusted because they often try to corrupt and domestic man. 

In many Romantic works, a male enters the wilderness and strives survive on their own, the Romantics believed they were living honestly and deliberately (think of Thoreau's "Walden" as the classic example).

Now contrast that with what happens to Frank, Kenny, and Tub when they enter the wilderness to go hunting.  Unlike the romantics who found truth and power in natural and the wilderness Wolff's characters get lost (Tub literally gets lost while hunting), betray each other (Kenny begins shooting things in a maniacal fashion, eventually killing the farmers old dog, which lead to Tub shooting Kenny, which leads to their failed rescue), and eventually get caught up in the trivialities of their own lives (Frank ordering Tub dinner after he tells him about his affair with the baby sitter and Tub gladly devouring it after confessing to Frank that he has been a glutton all along and never attempted to diet at all.  Of course, all of this occurs while Kenny is freezing to death in the back of the truck).