Floors
The descent, floor by floor.
- Floor 1 — The TutorialLethal tutorial: achievements, loot, safe rooms, boss gates, the stairwell down.
- Floor 2 — The Second FloorMonster neighbourhoods and the first real boss structure.
- Floor 3 — The Over CityA populated urban-fantasy world replacing tunnel survival; quests, settlements, the Scolopendra story.
- Floor 4 — The Iron TangleEvery subway system that ever existed on Earth, tangled into one transit knot; a floor-wide logic trap.
- Floor 5 — The BubblesSelf-contained worlds in four environmental sectors, joined by unstable gates.