The 'things' which he mentions in the title include the physical objects which the soldiers carried with them, and the emotional thoughts and pressures which they had to carry in their minds. These physical and emotional loads were symbolic of and filled with fear, love, grief and their longings. O'Brien specifies the physical loads which all the soldiers carried with them. Many of them were things of common use in the war, while apart from these soldiers also carried things of personal value to them.
Soldiers basically carried with them an assault rifle, which is usually carried by soldiers of low rank. Some of them also had grenade launchers, multi-purpose two-pound poncho and even magazines of ammunition. Some included mosquito repellents, chewing gums, marijuana and pocket knives. Their priorities could be seen from the things they possessed. These loads were taken along because it would be of physical help to them in the war. There were other things which gave them psychological support, which made them emotionally strong in facing the war. These things were of great value to them. Lt. Jimmy Cross, carried with him reminders of Martha, his love. Cross has the letters which she sent to him. He occasionally took them out and read, hoping that she would be his sometime in future. He also keeps in his mouth a good-luck pebble, which was given by her. Henry Dobbins was peculiar because he found his girlfriend's pantyhose important and put it around his neck. Ted Lavender found it imperative to calm himself down and so always kept tranquilizers with him. Kiowa preferred the New Testament and kept it safe.
While they literally carried these things, they also carried emotions, which were emphasized with their possessions. Cross keeps Martha's reminders and Dobbins puts the pantyhose around the neck in remembrance of their love. It gives them comfort in the war to think about the girls they love. Compasses and maps are also carried by Cross, because he has the responsibility of the lives of his men during the war. Some of them like Lavender carry fear which never leaves him. Apart from all these, the soldiers have the reputation, which puts them under a lot of pressure. They have the responsibility to fight courageously forgetting all their personal thoughts and grieves. Whatever they feel, it must not be taken out when facing their enemies and this demanded a lot of strength. As it is mentioned in 'On the Rainy River,' many of the soldiers might have been forced into war like O'Brien was and they may not have enough strength to fight or face the enemies. Their internal conflicts together with a repulsion towards war, increased their mental sufferings. Even after the war, the soldiers have psychological burdens with the thoughts about their dead fellow-mates and the terror of the war. They are never relieved of its frightening experiences and its thoughts.
Thus, the physical and emotional loads which they carry with them to the war are what the author means by 'things.' The things that they carried were of great importance to them, because all of it either physically or emotionally helped them face the war. While the rifles gave them safety, the mosquito repellents made survival easier. The religious books made them brave and courageous and the reminders of love performed a role of relieving their thoughts from the terror of war and fear of lives to a happier and safer future, where they would unite with their