The game has two modes to choose from, one in which the player has to spread the disease to destroy the entire human race, and the other in which the player has to develop a cure to save the entire human race. There are difficulty levels to choose from in both modes, and new players can choose the easiest one to start the game.
In the former, the characteristics of a disease are controlled by its onset symptoms, and while the diseases at our disposal are numerous and vicious, again, humanity is no longer living in the dark ages of the Middle Ages. Advanced medical research has enabled mankind to understand most diseases; progressively more widespread medical facilities have enabled mankind to cure diseases effectively; and centralized, relatively efficient governments have been able to control population movements and inhibit the spread of viruses. Thus, Plague Inc. also requires your mind. Choose your country carefully, as this will determine the course of the disease strain: the level of climate, population and economic development varies greatly from region to region. In hot regions, you should improve the heat resistance of the disease; in humid regions, you should develop the moisture-loving nature of the disease; in rich regions, you should take into account the resistance of the disease. At the same time, if the area is too remote, the disease will not spread easily; if the population is too small, valuable time will be wasted in the initial stages. Neglecting any point can be a big mistake. If we can't kill humans, we can't win the ultimate victory. But if we kill humans too quickly, we will undoubtedly raise their alertness. Therefore, how to balance the infectiousness, severity and lethality of disease strains is certainly an important topic.
In the latter antidote storm mode, the player will play as a medical doctor who develops the antidote. At this point you will be faced with 3 puzzles: prestige value, rebelliousness, and pathogens. Each puzzle will be the key to the game, and only by dealing with them properly will you be able to succeed in the game.