There was no Hardmode in version 1.0.0. The game featured only a handful of bosses: Eye of Cthulhu Eater of Worlds Skeletron (widely considered the "final boss" at the time) King Slime
You could not build directly from your inventory; you had to place items into your hotbar first. terraria 1.0.0
Many features that are now considered "quality of life" essentials were notably absent or functioned differently in version 1.0.0: There was no Hardmode in version 1
There were no wings or specialized mount systems; players relied on tools like the Grappling Hook and Flippers for mobility. terraria 1.0.0