Negative Levels

Negative Levels are levels below Level 0. It is not known how many of them exist, but so far 4 have been documented. You can enter the Negative Levels by going through darker walls while in the Positive Levels. Basically, if you no-clip whilst in the backrooms, or fulfill other anomalous criteria, it leads you to the Negative Levels.

Description
Reports say that unlike the usual dim lighting and mono-yellow, the Negative Levels have stagnant and eerily constant lighting, and the walls appear to be light grey. Air vents can be found in some of the lower Negative Levels, but only go in them as a last resort. Echoes travel farther, and it seems to get colder the longer you stay there. It is said that the human imagination has a severe influence on a person's perception of these places. Some have even claimed that an all-seeing malicious Entity watches over the Negative Levels, although this never been confirmed, as it has been deemed physically impossible to pass through to Level -5 without experiencing fatal physical and psychological damage.

Level -1
Level -1 is one of the largest levels in the Backrooms, as it seems to consist of an infinite hallway. Doors on either side lead to Levels -2, 0, and 2. You cannot access Level 1 from here. It is recommended that you try to exit to Level 0, though, if you are feeling adventurous and have equipment, it is safe to exit to Level 2. It is strongly advised to never go near doors leading to Level -2.

Level -2
Level -2 consists of only hostile Entities, and some of the most sinister at that. Explorer Aryaman barely escaped with his life from a gigantic evil creature in this level. Almond Water is available at this Level, although the safeness of this water is questionable. Falling down shafts from other levels can also lead to Level -2. It is difficult to escape, yet this level seems to draw in explorers. You shouldn't go down to -2 at will.

This level is thought to be split into multiple significant sections, or areas. Most of these sections (apart from the area listed above and the area known as "The Hall of Dull Flames") are unconfirmed and should be regarded as rumors until confirmed to exist by reliable sources. The area listed above is known as “The Pool”.

The section known as "The Hall of Dull Flames" is still relatively unknown, as there have only been two encounters with the area. It differs from the best known section greatly. u/LoggoMyDoggo stated that the level resembles the layout of Level 0, but the walls are a terribly stained baby blue with a white carpet equally stained. The fluorescent lights line the ceiling, but give off no light, providing nothing to the level but the maddening hum buzz present in previous levels. The walls are lined with lanterns that house flames that provide an ominous blue hue to the room. The color of the flames change color at random intervals, and it has been rumored to be linked to dire consequences to anything that moves in the light of the red flame. The distorted sound of a piano can be heard in the distance of the level, playing anything from Mozart to Tip-toe thru the tulips. Skin Stealers inhabit this section, and they also obey to the red flames of the room; halting any movement when the red flames of the lanterns glow. No other entities have been reported on this section, but u/LoggoMyDoggo reported seeing the red vest of the child Facelings hanging on one of the walls.

There is another reported section, known as "The Abyss", but akin to The Hall of Dull Flames, it is still very much unexplored, as only 1 person has reported exploring it so far: u/Minion142. The Abyss seems to be a never ending room of darkness stretching on for what seems like miles. Only one entity has been found here.

There is a fourth reported section of Level -2 known as The Kafkaesque Maze also explored only by: u/Minion142 Which is a purple hedge stretching on for miles...it is also the hub for a being known as The Shavic.

There is one report of a sort of "hub" connecting the various sections of Level -2, resembling a hotel lobby, but this is unconfirmed. Furthermore, it is likely not accessible from within the other sections of the level.

Level -3
Level -3 is still mostly unexplored, but someone has managed to retrieve a picture. It seems to be built fully out of mirrors. Entities, which are mainly hostile on this level, are common, about as common as on Level 3. There are several types of entities in this level, including strange floating glass icosahedra nicknamed "disco balls", the omnipresent hounds, and possibly an unseen entity that changes your appearance in the mirror, although it could simply be the Troxler Effect In some cases objects can pass through certain mirrors in -3 and become physically reflected; doing this is not recommended, as it seems to be irreversible and is rumored to be dangerous. Under absolutely no circumstances should one attempt to pass through a mirror on -3 oneself. One possible theory supported by the few explorers that have returned from this specific space alive is that one can only utilize the full transportation powers of the mirrors if they have forsaken their sanity.

Apart from sounds made by hounds and the very occasional human explorers, the level is entirely silent. WiFi is available — it can be accessed similarly to the network on Level 3, except the password is instead "itsawyou". Wireless charging ports are occasionally available, taking the form of unmarked, seemingly random locations on the floor.

Level -4
Level -4 is a huge, open, snowy forest, expanding for hundreds of thousands of miles in each direction. It is inhabited by animals that look similar to animals on Earth, like bucks, bears, snakes, and birds, with some differences, such as wasp-like insect eyes present among mammals and empty-white human eyes on snakes and the like. These animals are violent and have very tough armor-like skin, making firearms and sharp objects quite inefficient against them. The meager few that have wandered into this Level have also reported something akin to distorted smiles appearing on the faces of the hostile wildlife and even the trees. There are supposedly entrances to a fifth negative level here, but due to the chaotic nature of the Negative Levels and unreliable information, the only individual who claims to have made it to an entrance hardly remembers what Level -5 truly was.