In the story "The Most Dangerous Game", what was the irony of the whole story and how does it create the theme and author's tone?

In "The Most Dangerous Game" the irony--a contrast between what is expected and what actually happens--is the fact that Rainsford, who responds with umbrage to General Zaroff at dinner the first night that he does "not condone cold-blooded murder,"  becomes a cold-blooded murderer himself.  For, after being filled with terrror and feeling like "an animal at bay," Rainsford escapes his predators and returns to become himself the predator, who after killing General Zaroff, feels as did Zaroff, no compunction:  "He had never slept in a better bed, Rainsford decided."