Pathogenic is a 2D roguelike twin-stick shooter that immerses players in the role of a parasite battling the immune system of a human host. The game challenges players to adapt and evolve, allowing them to hunt down enemy cells, extract their organelles, and incorporate these into their own body. This evolution is crucial for survival as players must create powerful builds to dominate the immune defenses they face.

The gameplay features extensive customization, enabling players to loot and assemble their unique pathogen from a variety of organelles, enhancing movement, power, and attack capabilities. With diverse enemies, including immune cells and rival parasites, players can engage in intense battles within a procedurally generated landscape that represents different biomes of the human body. The soft-body physics simulation adds a layer of realism to the action, ensuring each gameplay experience is both unique and engaging.