Terraria is a 2D sandbox action-adventure game with platforming and role-playing elements. Players create a character and are placed in a procedurally generated world where they mine resources, craft equipment, build structures, and fight enemies. Progression is driven by defeating bosses that unlock new tiers of items, biomes, and challenges. The game features a class system based on equipped gear, NPC recruitment tied to achievements, and supports both single-player and multiplayer modes. Terraria also includes official modding support through the tModLoader framework.