Circleroyale is an agar.io-style multiplayer .io game built in s&box (Facepunch's C# engine), where players control a neon glowing cell that eats food and smaller players to grow, splits into multiple bodies with mouse-aimed splitting and mass-ejection, faces bots with advanced AI (split-hunting, team feeding, regrouping), and offers free-for-all or 2/3/4-player team battle modes with Steam lobby hosting, a room browser UI, disconnect auto-reconnect, and host-authoritative networking with owner-side movement simulation.