Operation C is also known as Contra (ン Kontora) in Japan and Probotector in the PAL area. The story revolves around the protagonist Bill Rizer, a soldier on a journey to stop an evil force trying to grow alien cells in their base. As Bill Rizer, your mission is to break into the enemy base and destroy all the enemies you encounter. In the beginning, you will be provided with 3 lives, if you encounter an enemy, hit a bullet or fall into a deep pit you will lose a life. In addition to completing a level, you will receive an extra life. There are some levels that require you to control the character from the side view, while others are from the top. During the game, you will have to fight with powerful bosses, but they also have certain weaknesses that require you to quickly find before they are destroyed.