This War of Mine is a survival-themed strategy simulation game in which players control a group of surviving civilians in the war-torn city of Pogeren. The main goal of the game is to control the characters through various materials and tools to survive the war. Most of the player-controlled characters have no military background or special survival experience and require constant player intervention to stay alive. It is the player's responsibility to keep the character normal in terms of health, hunger, and mood until the end of the war after a random number of days.

During the day enemy snipers will prevent survivors from going out and exploring, thus leaving players to use collected materials in the shelter to make tools, trade, upgrade workbenches, reinforce fortifications, cook, and heal characters. At night, players will have the opportunity to go out and collect valuable resources from neighboring areas to sustain their survival. Friendly survivors may seek assistance or trade, and it is up to the player to choose whether to help these people for pay or to kill them; while some of the survivors who are obviously hostile or turn hostile because you offend them, you can only choose to sneak out of their sight to get the needed supplies or just take them by force with weapons. Players can build a radio in their shelter to listen to useful information such as weather warnings, news about the city's economic market and news about the war to help them plan appropriate upgrades and complete their missions.

At the beginning of the game, the player can control 1-4 characters, and the player's actions will change the type of ending each character will have at the end, each character has six endings, in addition to the death, suicide, and runaway endings, there are three surviving endings. The game starts with Bruno and Pavlé as the characters in the one-week game, plus a random selection of Marco or Katia. Each character has one or two traits that will help or hinder the player in the game. Some traits are helpful at certain moments, others are effective in the long run. For example, Bruno has a trait called Good Cook that helps players use fewer ingredients and less water when cooking. In total, there are 12 characters available to players