A Level is the name we've given each unique room inside the Complex, which is an umbrella term in itself.
These Levels are never completely identical to each other in appearance, however, some may function or be structured similarly. The first 9 Levels are separated from the rest of the Levels because they are the very beginning of the Complex and are a set of Levels that are incapable of sending you anywhere but further inside the Complex, although Levels beyond Level 009 are able to send you back to one of the first 9 Levels. Level 000 does not count as part of one of the 9 Levels as once you escape from it once, you can never return back there, or can you?
But can it always get deeper? - Enigmatic Levels
﹥ Level 000 - "The Complex"
- Floor 000-2 - "Remodeled Mess"
﹥ Level 001 - "Lurking Danger"
﹥ Level 002 - "Pipe Dreams"
﹥ Level 003 - "Electrical Station"
﹥ Level 004 - "Abandoned Office"
﹥ Level 005 - "Terror Hotel"
﹥ Level 006 - "Lights Out"
﹥ Level 007 - "Thalassophobia"
﹥ Level 008 - "Tunnel System"
﹥ Level 009 - "The Suburbs"
- Floor 009-1 - "Perpetual Community"
﹥ Level 010 - "Field of Wheat"
﹥ Level 011 - "The Endless Skylines"
﹥ Level 012 - "Whiteout"
﹥ Level 013 - "The Apartments"
﹥ Level 014 - "???"
﹥ Level 015 - "Neoteric Passage"
﹥ Level 016 - "Unorthodox"
﹥ Level 017 - "Cargo Ship Corridors"
﹥ Level 018 - "Memories"
﹥ Level 019 - "Crawlspace"
﹥ Level 020 - "Barren Storehouse"