is the conflict external or internal ?

Ha, I love this story. The Most Dangerous Game is purely escape fiction. This means that the conflict is largely external. Rainsford is pretty much perfectly good and General Zaroff is pretty much perfectly evil. That is your conflict right there. You could make an argument that Rainsford struggles with the ethics of hunting and animal cruelty. This, however, is a stretch because the characters are so one dimensional and the plot so preposterous. The story is pretty much man vs man but it is a fun read!