The title "The Most Dangerous Game" has two significant meanings. The first meaning comes from Rainsford's perspective; he is involved in the most dangerous game he has ever played as he fights for his own survival while being hunted. The second meaning comes from General Zaroff's perspective. Game is a general term used for animals that are being hunted. Zaroff, having hunted all types of animals, decides to hunt humans. He considers humans the most dangerous game because unlike other animals that act on instinct, humans are able to reason, making them a more difficult track and kill.
"Game" means animals that are hunted. "Game" also means any contest engaged in for recreation, such as football or chess. In Zaroff's crazy world the most dangerous game (animal) is man because he has a brain and can think of ways to fight back. He can also devise weapons and man-traps. Zaroff regards the contest between himself and his human prey as a game (a playful contest). In Rainsford's case, he accepts it as a game to be played on Zaroff's terms and on Zaroff's island. Rainsford is really dangerous because he is just as experienced in such things as tracking and wilderness survival as the man hunting him. Rainsford is also dangerous because he knows ways of making lethal traps for Zaroff, and he almost gets him twice before finally finishing him off in the end.
An interesting film adaptation of "The Most Dangerous Game" is available on DVD. The original film was made in 1932, but the photography, sound, and other technical aspects are very good for the period. The actor playing Zaroff has a hard time being convincing because it is such a slanted character--a sophisticated gentleman who enjoys killing humans for sport.