From the beginning, "Shooting an Elephant" highlights Orwell's use of irony. The title suggests that the narrator, possibly Orwell himself, actually plans to shoot an elephant. In fact, he takes his gun not to shoot the elephant: "I took my rifle, an old .44 Winchester and much too small to kill an elephant, but I thought the noise might be useful in terrorem" (paragraph 3). In fact, he just wants to make a show of shooting the animal.
Another example of irony occurs when the "coolie" is trampled and killed by the elephant. By the end of the essay, the younger men agree that the elephant's life was worth more than that of a coolie. Therefore, the elephant shouldn't have been shot after all. It is ironic that the elephant's life is more valuable on a monetary basis. As well, it is ironic that the elephant is seemingly shot for no reason other than entertainment and later for its meat.
Irony is a foundational element in this story. All of the above answers exist and there are several others. One additional way irony is used is through the role of the narrator. In theory, he is the one in charge - he is the protagonist of the work. But, Orwell uses his position to show the evils and futility of Imperialism. Orwell notes that he felt sorry for the Burmese people because of the torture they went through at the hands of the British, and hated them at the same time because of the torture they put him through daily. In the end, the man in charge, the protagonist, winds up simply being a puppet on the string of the Burmese people. He shoots the elephant to avoid looking like a fool in front of all of those people instead of being the leader he is supposed to be.
A good question. The primary irony used in "Shooting an Elephant" is situational, though this is supported by tone. The narrator sounds calm and almost detached throughout the piece, even when he's discussing very upsetting events. The essay opens with a discussion of him being hated, yet he seems quite a civilized person, and one of the least likely people to be hated. He wants to help people, but must do so by killing. The essay ends with him saying he was glad the coolie had been killed, because it gave him a legal reason to kill the elephant: he has to be glad someone has been killed, so he can protect people. That's ironic.