Buck Rogers had once fought in the cold war, a pilot sent into outer space to destroy a Russian weapons platform. He was successful, but his success destroyed the planet, as nuclear war was launched, and you went into a centuries long cryogenic sleep, abandoned by the people who could not retrieve you. In the centuries that he slept, Earth colonized the solar system. There are large groups of people on Mars, Venus and Saturn. The colonies once existed to bring resources back to an Earth that had problems sustaining itself.
But the intervening centuries brought a power shift. Now Earth is at the Mercy of the interstellar alliance RAM—formerly the Russian-American Mercantile, but now the superpower, based on asteroids surrounding the planet Mercury. Mercury exploits the Earth for resources, at the expense of Earth's population. Earth has fallen into barbarism, except for one small light—the New Earth Organization (NEO). These "rebels" consider themselves freedom fighters, and they are fighting for Earth's freedom from the interstellar powers. Awakened from centuries long sleep in the 25th Century, Buck Rogers becomes an ancient military hero and symbol of earlier times. As he is brought up to date, he decides to join the the NEO, to fight for his home planet.
Buck Rogers: Countdown to Doomsday is a role-playing game similar in gameplay, interface, and visual styles to the Dungeons & Dragons games by SSI, despite the completely different setting and sci-fi scenario. The player's first task is to create a party of six characters from a choice of five classes (Rocketjock, Warrior, Medic, Rogue, and Engineer) and six races (Human, Desert Runner, Tinker, Venusian, Martian, and Mercurian). Then, these six new NEO recruits are trained, and are thrust into the battle for Earth.
There are several navigation modes in the game. The player can navigate the space ship on a top-down map of the Solar System, choosing planets to land on. Hostile ships may attack the player-controlled ship in this mode. Landing on a planet usually positions the heroes on a local overworld map. Finally, navigation in individual locations (towns and hostile areas) is done in first-person perspective, with pseudo-3D environments. Combat is turn-based and is viewed from an isometric perspective; characters are represented as icons and can be freely moved on the battle field.