Some examples of foreshadowing in "The Most Dangerous Game" by Richard Connell are the warning about how sailors feel about Ship-Trap Island, the conversation between Whitney and Rainsford about hunting and the jaguar, and the scream Rainsford hears as he swims.
When Whitney points out the island, he explains to Rainsford that "sailors have a curious dread of the place. I don't know why. Some superstition—." Rainsford is so focused on the island that he ignores the warning and just tries to see land through the dark night.
Connell foreshadows what happens on the island by alerting readers that something is wrong with it. While not all superstitions are based on reality, it's clear that something is amiss. If Rainsford had paid more attention to Whitney's words, he might have avoided the entire encounter with General Zaroff.
Another example of foreshadowing in the story is the conversation between Rainsford and Whitney about hunting in the Amazon; they're traveling there when Rainsford falls off the ship. Connell writes:
"The best sport in the world," agreed Rainsford.
"For the hunter," amended Whitney. "Not for the jaguar."
"Don't talk rot, Whitney," said Rainsford. "You're a big-game hunter, not a philosopher. Who cares how a jaguar feels?"
"Perhaps the jaguar does," observed Whitney.
Rainsford goes on to tell Whitney that the world has two classes: the hunters and the hunted. Rainsford identities himself and his companion as hunters. Unfortunately for him, he'll experience the fear and panic of the jaguar soon when he arrives on Ship-Trap Island and plays the game with General Zaroff.
Finally, the scream that Rainsford hears when he swims toward the island foreshadows the game that Zaroff hosts. It says that the sound "came out of the darkness, a high screaming sound, the sound of an animal in an extremity of anguish and terror. He did not recognize the animal that made the sound." Connell goes on to say that Rainsford didn't even attempt to identify it.
The sound of the animal screaming in pain—likely a human—foreshadows Rainsford becoming the hunted as Zaroff pursues him across the island later in the story.