I have a question to ask about the sniper: What do you find interesting and dramatic about the story?
The sniper in the story is mysterious because his only identity is that he is a soldier. The author takes us through the action of the story to express his feelings about war, especially civil war. A civil war is one in which your enemy is a person of your own country. In the American Civil War, Americans fought Americans, sometimes even their brothers. This is true of the civil war in Ireland.
The most dramatic part of this story is the surprise ending where the sniper discovers that the other sniper he has just killed is his brother. He thought maybe he might know him and that's why he's curious to see who he is. The reader doesn't know how the sniper feels about killing his brother, underscoring the author's theme of what war does to a person.
The thing I find most interesting and dramatic about The Sniper is that a country, Ireland, was so involved in a Civil War that it pitted two brothers against each other. It is amazing to me that a country would not want a unified government. It takes a lot of work to unify a country but with compromise, time and effort, a peace treaty could be the end result and there could be a government where everyone feels safe. If this occurred in countries then we wouldn't end up losing our most precious and valued possession, "FAMILY".