The player is who assumes the role of a doctor and is tasked with viruses. In this falling block puzzle game, the player's objective is to destroy the viruses populating the on-screen playing field by using colored capsules that are dropped into the field.
The player manipulates each capsule as it falls, moving it left or right and rotating it such that it is positioned alongside the viruses and any existing capsules. When four or more capsule halves or viruses of matching color are aligned in vertical or horizontal configurations, they are removed from play. 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.
Players can select the degree of starting difficulty any time a new game is started. The initial level chosen is a value between zero and twenty that determines the number of viruses to clear, and the three game speed options change how fast the capsules fall in the bottle. The player's score is based solely on the elimination of viruses, not on the time taken to complete the level or the number of capsules used. The game speed is also a factor in how the game calculates scoring; higher speed levels yield more points.