How does the republican sniper resolve his conflict with the second sniper?
The republican "resolves" his conflict with the enemy sniper by shooting him. He sits on a rooftop and lights a cigarette. The smoke gives away his position and the enemy fires in his direction. Then an old woman informs an enemy solider in an armored car of the republican sniper's location. He decides he must shoot the soldier and the woman to protect himself. He does so but is hit by the enemy sniper in the process.
The republican sniper comes up with a plan to fool the enemy sniper. He puts his hat on top of his rifle and holds it up. The enemy takes a shot. The republican sniper holds the rifle in his hand and dangles it lifelessly over the edge of the roof. He drops the rifle to the street to make it appear that he has been shot and killed. The ruse works and the enemy sniper stands up. The republican shoots his enemy with a revolver. His enemy falls off the roof onto the street below. The republican climbs down to find that his enemy is "his brother."
The republican sniper is a young man. His youth is emphasized to show how he was once naive and innocent. He must commit himself to being a single-minded soldier, capable of killing without hesitation. He must do this in order to survive. This is the harshness of war which seems even more tragic in a war in which brother is pitted against brother.