Unstable SMP FFA is a Roblox experience from Insomnia Studios that combines free-for-all combat with a battle simulator based on the Unstable SMP universe. Players spawn as recognizable characters with their associated gear and fight other players using Minecraft Java 1.21.11-inspired combat, including spear lunges, mace attacks, elytra movement, wind charges, pearls, tridents, and TNT carts. The experience supports PC, phone, and controller play with rebindable controls.

Progression centers on learning each character and arena while taking on increasingly demanding battles. Players can choose from 28 characters, unlock The Wraith, join Duels, practice against a dummy, or enter Juggernaut Events. The simulator mode lets solo players or parties of up to 10 fight armies of up to 100 soldiers across three rotating arenas, while updates can expand the available combat and event content.