The Backrooms Update

The dimension is made of rooms that continue without a fixed end. Some floors are not solid: thin spots appear across the surface of the overworld, where patches of ground look exactly like floor but give way under weight. A player who walks over one falls through and arrives in the dimension. A portal opens after the first crack, and it runs both ways, so a return trip always leads back to the same spot in the overworld, which can be found again.

The dimension, called the Complex, is stacked sixty-four floors deep. Each floor is dark, sorted and themed, with stretches that shift from one area to the next. Yellow walls with damp carpet and endless buzz from lights, pale quartz pool rooms with shallow water that never seems to end, and wide green grasslands under a flat blue sky all appear. A shaft opens into the floor below, and once the ground gives out, a pit can swallow ten floors at once. Lower floors grow darker and lonelier, and a fall through the lowest floor brings the player back to the top.

The mod draws its look entirely from vanilla assets, which keeps it light and compatible with shader and resource packs. It is a standalone NeoForge mod and needs no other mods. Files are published for 1.21.1 – 1.21.11, and the latest NeoForge file is 2.0.0 for 1.21.11.