Ray Bradbury had a very florid writing style, rich in description and metaphor, and "A Sound of Thunder" is no exception. Consider the following passage, when Bradbury describes the Tyrannosaurus:
It came on great oiled, resilient, striding legs. It towered thirty feet above half of the trees, a great evil god, folding its delicate watchmaker's claws close to its oily reptilian chest. Each lower leg was a piston, a thousand pounds of white bone, sunk in thick ropes of muscle, sheathed over in a gleam of pebbled skin like the mail of a terrible warrior. Each thigh was a ton of meat, ivory and steel mesh. (Bradbury, "A Sound of Thunder")
Note how dense and visual that description is. That density of imagery, metaphor, and descriptive language is one of the hallmarks of Bradbury's writing style. One can find similar passages across this story, and across Bradbury's larger body of work.
In addition, you can also find allusions in this story. Consider the scene when Travis describes the repercussions of changing the past. Here, Bradbury writes:
It is comparable to slaying some of Adam's grandchildren...With the death of that one cave man, a billion others yet unborn are throttled in the womb. Perhaps Rome never rises on its seven hills. Perhaps Europe is forever a dark forest, and only Asia waxes healthy and teeming. Step on a mouse and you crush the Pyramids. Step on a mouse and you leave your print, like a Grand Canyon, across Eternity. Queen Elizabeth might never be born, Washington might never cross the Delaware, there might never be a United States at all. So be careful. Stay on the Path. Never step off! (Bradbury, "A Sound of Thunder")
Note the various references Bradbury makes in this passage: he mentions Adam (referring to the story of Adam and Eve), along with Ancient Rome, the Pyramids, Queen Elizabeth, and George Washington, but he does so in passing (without explaining the intricacies of who he is referring to or why he is making that reference to begin with). These are all examples of allusions.
Finally, I think Bradbury's use of foils is also worth discussing. Observe the contrasts between Eckels and Travis. Eckels is a tourist paying Time Safari to take him to the Cretaceous, whereas Travis works for Time Safari as a guide. Eckels, despite his enthusiasm about going hunting in the past, is anxious and high strung. Travis, on the other hand, is composed, confident and decisive. Travis has far greater awareness as to the risks of time travel, and has to explain those risks to Eckels. Finally, as the story concludes, we see Travis killing Eckels, after Eckels has accidentally altered history.