Ultimately, similes (like metaphors) are defined by their use of comparison to link together two otherwise unrelated subjects. This is done in order to draw heightened attention to a quality that the two subjects share. Indeed, the only real difference between a simile and a metaphor is that similes draw the reader's attention to this act of comparison through the use of the word "like" or "as." If you were to remove that one word, then the simile can be rewritten to become a metaphor (and the same applies vice versa). "The Most Dangerous Game" is filled with this kind of figurative language.

For example, take the scene where Rainsford, still on his boat, first hears the sound of gunshots (and proceeds to fall into the sea). Here, Connell writes,

He strained his eyes in the direction from which the reports had come, but it was like trying to see through a blanket.

Of course, Rainsford is not actually looking through a blanket in this scene, but the image gives a striking impression of Rainsford's struggles to detect where the gunfire had come from.

For another example, consider the image of Zaroff's servant, Ivan, who is holding Rainsford at gunpoint:

The revolver pointing as rigidly as if the giant were a statue.

Here we have here an image by which Ivan's stillness makes him statue-like, and, through specific use of the word "as," the sentence draws the reader's eye directly to its use of this comparative effect.

For one last example, the following sentence simultaneously combines personification, metaphor, and simile all at the same time:

An apprehensive night crawled slowly by like a wounded snake and sleep did not visit Rainsford, although the silence of a dead world was on the jungle.

In this particular instance, we can point towards three separate literary effects. First, there is personification, with night specifically being labeled "apprehensive." Next, we have the simile, where Rainsford's restlessness and the slow passage of time is compared with the crawling of a wounded snake. Finally, there is the metaphor where the jungle's silence is compared to that of a dead world. Note, however, the difference between the simile and the metaphor: similes call attention to this comparison whereas metaphors do not.

These are just a few examples of similes that Connell uses throughout the story. You can find many more within the text.

Another example of a simile can be seen when General Zaroff expresses surprise at Rainsford's values, telling him that they're out of place, "like finding a snuff-box in a limousine."

Zaroff naturally assumed that an experienced hunter like Rainsford would be on the same wavelength as him when it came to hunting human quarry. He thought that Rainsford, of all people, would understand his desire to take his blood-stained hobby to the next level.

But Rainsford's not like Zaroff at all, at least not in this regard. To Zaroff, Rainsford's values seem strangely out of place for someone of his background. Just as Zaroff wouldn't expect to find a snuff-box in a limousine, he finds it hard to believe that a big game hunter like Rainsford doesn't share his enthusiasm for hunting human prey.

A simile is a literary device in which two unlike things are compared for effect using "like" or "as." A well-known example is a line from William Wordsworth's poem: "I wandered lonely as a cloud."

When the general is explaining to Rainsford how he traps his unsuspecting victims in their boats offshore, he describes the rocks in the sea as if they were were alive:

[G]iant rocks with razor edges crouch like a sea monster with wide-open jaws.

As Rainsford listens to the general's bizarre story, he finally accepts that he has almost no choice but to participate in the gruesome sport. Time passes slowly as he waits nervously for the departure hour:

An apprehensive night crawled slowly by like a wounded snake.

Once the hunt gets underway, he finds it difficult to evade the general and, as he flees across the island, realizes he has reached the edge of the dreaded Death Swamp. His foot is getting pulled into quicksand:

[T]he muck sucked viciously at his foot as if it were a giant leech.

A simile is a comparison of two dissimilar things that share similar characteristics, as if they were the same—using "like" or "as" in the comparison. 

For example, "You are the sunshine of my life" is a simile, comparing "you" (let's assume it's a woman) to "sunshine." While they share similar characteristics (both can make the speaker feel warm and happy, like the sun does), "she" will never give someone sunburn. It is not literal but figurative language—language not to be taken literally. It's a form of imagery that provides a description of a person or thing the reader may not know to something that the reader does know —in this case, the "sun."

In the story, "The Most Dangerous Game" by Richard Connell, one of the first similes is something that evokes an extremely clear mental image. Whitney is describing the "moonless Caribbean night" and notes:

It's like moist, black velvet. 

Note the use of "like," comparing the night to a heavy wet material (velvet). This description gives the reader (without being there) the sense that the air is thick, and it's hard to breathe.

Later Connell provides another simile:

The sea was as flat as a plate glass window.

This compares the surface of the water to the slick and smooth surface of glass, using (in this case) "as" for the comparison of the two.

When Rainsford meets Zaroff the first time, the author uses a simile to describe the General's appearance:

...his thick eyebrows and pointed military moustache were as black as the night from which Rainsford had come.

Once again, the night is used as part of a description; this time the black night is compared to Zaroff's facial hair.

Figurative language—using figures of speech—helps to provide vivid mental imagery for the reader. A simile is one of many literary devices used for this purpose.