Event Long Gone Days takes place on Earth in the fictional country of the Core with an unknown location. Each resident of this place is trained in a certain job from birth. When people become adults, they are already qualified as an expert in their field. The player follows Rourke, a military sniper who has never been to the rest of the world or the surface.

The central character receives a new task, during which he goes to help the Polish troops in Kaliningrad. The gameplay is presented in the form of a role-playing adventure with turn-based battles. In shootouts, the user is able to choose which part of the body to hit the opponent. The morality system increases or decreases, depending on the choices and actions of the gamer during dialogues, battles or solving problems. On your journey you will need to control a squad of soldiers, and each of them has its own characteristics and additional abilities.

NPCs speak their native language. It depends on what country the protagonist and his partners are in. The user will need to hire interpreters to understand what people are saying in other languages. As the player progresses, he will encounter dozens of side quests and merchants. In addition to turn-based encounters, there are shootouts with a first-person view. Visual novel elements are introduced as the project focuses on an emotional story and plot with non-linear choices.