IO games are a genre of online multiplayer games known for their simplicity and addictive gameplay. These games, such as Agar.io, Slither.io, and Diep.io, feature basic graphics and straightforward controls, but they offer deep and competitive experiences. Players typically control a character or object that must grow or survive by interacting with other players in real time. The objective is often to dominate the game space by becoming the largest or most powerful player. IO games are highly engaging due to their real-time nature and the constant presence of other players, providing a thrilling and competitive gaming experience.