ONCE / однажды is a first-person adventure game set in an alternative post-Soviet space. As a volunteer, you are sent to conduct an unscheduled inspection of power plant points. You are not Enlightenment's only chance for salvation, but small deeds lead to something bigger. Perhaps this story is about you.. Explore the presented territories with radiation, mutants and armed opponents. Uncover secrets and seek the truth!

At the moment, in Early Access the player has access to the starting location, several tasks, story dialogues and other actions.