Bacterial Takeover is set in a fictional Universe. Some of the planets are the same as in our Universe, like Mercury and Mars, or Earth, which even has a population that is roughly similar to our world.
Most of the lore and information on the galactic history is revealed through planet and mineral descriptions.
Many of the planets that the player visits at some time have been inhabited by various civilizations, such as planet Atreria and Dospunus. Some parts of planet descriptions can change after entering a Black Hole, which sends the player to an alternate timeline.