Dr. Mario is a puzzle game (very similar to Tetris) featuring Dr. Mario trying to eradicate viruses in bottles. For this, he launches capsules of different colors to make the bacteria disappear. It has been re-released many times on several Nintendo consoles.

The gameplay is simple: Dr. Mario has several capsules of different colors. A color can eradicate a virus of the same color.
For example, to eliminate a blue virus, it takes at least three blue capsules to touch it vertically or horizontally. If two blue viruses touch each other, to beat them, it is enough that there are at least two capsules of the same color which touch them horizontally or vertically. The same example can apply with the colors red or yellow as well, but with the respective viruses.

The higher the levels, the more bacteria there are to eliminate. You can choose the speed of the game, choose the starting level or even change the music.