The game is set on the planet Mobius, which is inhabited by bean-like creatures. Doctor Robotnik conceives a plan to bring terror to the world by kidnapping the citizens of Beanville and turning them into robot slaves, and eventually creating an army that will help him rid the planet of fun and joy. To achieve this, he creates the "Mean Bean-Steaming Machine" in order to transform the bean-like creatures into robots. Putting his plan into motion, Robotnik sends out his Henchbots to gather all the bean-like creatures and group them together in dark dungeons so they can be sent to the Mean Bean-Steaming Machine.[1] The rest of the game's story revolves around the player character, "Has Bean",[2] and their journey to stop Robotnik's henchmen by breaking into the dungeons and freeing the bean-like creatures.
Dr. Robotnik's Mean Bean Machine is based on Puyo Puyo, a Japanese falling-block puzzle game. In the story, players must rescue Beanville from Dr. Robotnik and his army of Badniks. In Scenario Mode, the player plays against 13 increasingly challenging computer opponents. In the multiplayer 1P vs 2P Mode, two players battle against each other, and in Exercise Mode, players can simply practice.[3][2] The Game Gear and Master System versions feature an additional mode, Puzzle Mode, in which players must attempt to clear predetermined sets of beans.[citation needed] On each player's grid, groups of beans fall from the top of the screen and can be moved and rotated until they reach the bottom. When four beans of the same colour are matched together, they disappear from the grid, causing any beans above to drop.[4][5][6] These beans can trigger other matches, resulting in chain combos.[6] By performing chain combos, players can send grey "refugee beans" to hinder their opponent. These beans cannot be matched normally and can only be removed by completing a match adjacent to them.[7] A player loses when beans spill over the top of the board, leaving them unable to add more.[8]