Dr. Mario is a falling block tile-matching video game in which Mario assumes the role of a doctor, tossing two-colored medical capsules into a medicine bottle representing the playing field. This area is populated by viruses of three colors: red, yellow, and blue, which stay in their starting position until removed. In a manner and style considered similar to Tetris, the player manipulates each capsule as it vertically falls 1 unit of space at a time, able to move it left or right and rotate it 90 degrees in either clockwise or counter-clockwise. When four or more capsule halves or viruses of matching color are aligned in vertical or horizontal configurations, they are removed from play. Any remaining capsule halves or whole capsules which are now not supported by a virus or capsule will fall to the bottom of the playing field or until it hits another supported object, and any new 4-in-a-row alignments created from this will also be removed. The main objective is to complete levels, which is accomplished by eliminating all viruses from the playing field. A game over occurs if capsules fill up the playing field in a way that obstructs the bottle’s narrow neck.