in the story's last line on how good the bed was, the reader must assume that he has killed Zaroff. Whether he actually fed the general to the dogs (a "repast" is a meal) is never known. 

Yes, Rainsford did really kill General Zaroff. In the story, it says, "The general made one of his deepest bows. 'I see,' he said. "Splendid! One of us is to furnish a repast for the hounds. The other will sleep in this excellent bed. On guard, Rainsford....'" From this, we know that the two men are going to fight and that only one man will sleep in the bed and the other will be dog food. Because the next/last line states, "He had never slept in a better bed, Rainsford decided," we know that General Zaroff became dog food.

One could argue that Sanger Rainsford has the right to kill the maniacal General Zaroff in Connell's celebrated short story "The Most Dangerous Game." In the story, the talented Sanger Rainsford falls off a yacht in the middle of the Caribbean Sea and swims towards the nearby Ship-Trap Island, which is General Zaroff's private retreat. Shortly after arriving at Zaroff's impressive chateau, Rainsford joins Zaroff for dinner and is disturbed to learn that the general hunts defenseless humans throughout the island. Ironically, Zaroff shares a similar philosophy of life with Rainsford when he says,

Life is for the strong, to be lived by the strong, and, if needs be, taken by the strong. The weak of the world were put here to give the strong pleasure (Connell, 8).

When Rainsford refuses to hunt men with Zaroff, he becomes the general's next victim and experiences firsthand the feeling of being hunted in the wilderness.

Rainsford relies on his hunting and survival skills to avoid the general for three consecutive days. Throughout the course of the most dangerous game, Rainsford transforms into a fierce being, who feels like a "beast at bay." After surviving the game, Rainsford manages to sneak into Zaroff's chateau, where he surprises the general in his bedroom. At this point in the story, Rainsford still feels like a threatened animal and is willing to do anything to survive.

Zaroff formally agrees to a duel, and Rainsford ends up killing him. After examining the situation and recognizing everything Rainsford endured, one could argue that he has the right to kill Zaroff. By killing Zaroff, Rainsford is acting in self-defense and protecting his well-being. A man as maniacal as General Zaroff could also break his promise and attempt to kill Rainsford later on. The general has already proven that he does not respect or value human life and is a violent individual, which is another reason why Rainsford's actions are justified. Overall, Rainsford has the right to kill General Zaroff as retribution for his harrowing experience on Ship-Trap Island and to protect himself from being attacked later on.

In Richard Connell's "The Most Dangerous Game," whether Rainsford is responsible for Zaroff's death or not can be argued two ways. First, one could argue that Rainsford is responsible for Zaroff's death simply because he wins the final battle. Two men, seemingly of equal strength and wits, face each other to the death in Zaroff's room. The fight, therefore, is fair, and Rainsford wins by killing Zaroff. As a result, yes, Rainsford is responsible for Zaroff's death. Zaroff even accepts the terms of this fight and freely participates when he says the following:

"I see. . . Splendid! One of us is to furnish a repast for the hounds. The other will sleep in this very excellent bed. On guard, Rainsford."

On the other hand, one could argue that Rainsford is not responsible for killing Zaroff because he virtually turns into a beast that simply fights for its life. Therefore, the argument could be that Rainsford is so far past rational human thinking at the end of the story that he reacts like a beast. In fact, Rainsford claims the following:

"I am still a beast at bay. . . Get ready, General Zaroff."

When Rainsford speaks metaphorically about being a beast at bay, he might also be speaking from a psychologically literal sense. For example, Zaroff forces Rainsford to act like a hunted beast for three days and nights in a jungle. Due to the mental trauma inflicted upon him over the course of these days, Rainsford starts to think and behave like a beast in order to survive. A "beast at bay" means that it has been cornered and must turn and fight to survive. Therefore, one could argue that Rainsford is not responsible for his actions when he kills Zaroff because he has been driven to the point of irrational thinking--thinking like a beast at bay and not as a human. One might also say that Rainsford could probably plead insanity for killing Zaroff and not be held responsible for his actions.