Minecraft 1.2.7 Alpha -

Hardcore redstone engineers noticed that in 1.2.6, a redstone "dot" (dust placed alone) would power all adjacent blocks but not update them visually. 1.2.7 fixed the comparator-less update order, making vertical redstone ladders behave predictably for the first time. This is largely forgotten, but it was huge for the tiny early redstone community.

He saved and quit. Then he reloaded the world, just to be sure. minecraft 1.2.7 alpha

Just him, a punch-tree, and a sun that moved in chunks. Hardcore redstone engineers noticed that in 1

Because of this brief window, Alpha 1.2.7 became the "lost snapshot." Most players updated directly from 1.2.6 to Beta 1.0, skipping the intermediate fix entirely. He saved and quit

While many YouTube videos showcase gameplay of this version, it is typically a modified client (mod) intended for horror storytelling. Official versions from that era jumped from directly into the Beta phase.