.io games are simple yet highly engaging multiplayer games played online. These games often feature fast-paced, competitive gameplay with minimalist graphics and intuitive controls. Players compete or collaborate in real-time to achieve objectives like growing larger, scoring the most points, or dominating the arena. Popular examples include Agar.io, Slither.io, and Krunker.io. Known for their accessibility and addictive nature, .io games are perfect for quick and exciting gaming sessions.