Worlds can be Small, Medium, or Large when it comes to size have Classic, Expert, Master, or Journey when it comes to difficulty and contain Corruption or Crimson. RELATED: Open World Games That Have Very Little Story This is called the World Seed feature, and, as with the wacky world of Terraria mods and the sheer randomness of generated worlds, the possibilities are almost endless.
However, there is the option to manually input a code or word so that Terrariaplayers know exactly (or at least have an idea of) what they are getting into. When launching a new world in Terraria, players typically let the game create a random map for them to explore.