Level 0 is widely recognized as the foundational layer of the Backrooms continuum. This environment is defined by its seemingly endless corridors, adorned with faded yellow wallpaper, stained carpeting, and the persistent ambient hum of overhead fluorescent lighting. The spatial layout is disorienting by design, featuring nonsensical geometry, repeating segments, and occasional structural inconsistencies, all of which contribute to the psychological strain experienced by those traversing it.

Visual monotony, coupled with the uniform soundscape, induces a subtle but cumulative dissociative effect over time, which is suspected to impair perception and navigation. The level lacks any distinguishable landmarks, complicating orientation and increasing the risk of becoming permanently lost.

Access to Level 0 is achieved through involuntary or induced transition via suffocation in the overworld environment. Subjects who survive the transition report experiencing an abrupt, dreamlike shift before reawakening at the origin point of Level 0. This location is consistent across most cases and appears to be a fixed coordinate in the level’s topology.

Level 0 is assessed as moderately hazardous, not due to overt hostility, but because of its subtle psychological dangers and the presence of an anomalous predatory entity class, informally referred to as Skinwalkers. These entities are infrequent but pose a serious risk upon encounter, particularly in low-visibility zones. Additionally, unstable lighting conditions have been noted to provoke unease and complicate escape attempts.

No food, water, or rest opportunities are known to exist within the level, which raises secondary risks related to prolonged exposure.

Level 0 is distinguished by a variety of recurring environmental events that appear to be system-triggered or procedurally randomized. These include:

• Blackout Events: This event results in the permanent deactivation of all lighting across the level, plunging it into complete darkness. Restoration of lighting has only been observed under one known condition: if an intercom anomaly activates during or shortly after the blackout, broadcasting a repeated, distorted voice asking "Are you my friend?" Recovery of light appears to follow this event, although the mechanism remains unexplained.

• Flicker Events: A temporary malfunction of the lighting system, during which overhead lights flash rapidly in unpredictable intervals. These occurrences can increase cognitive stress and are suspected to correlate with other environmental changes.

• Intercom Anomalies: Wall-mounted intercom units may activate at random intervals. Initial broadcasts consist of generic announcements, but successive activations may introduce reversed speech, vocal distortions, or looping phrases. These messages may be tied to the level’s light control systems, particularly in blackout conditions.

• Auditory Distortions: Under certain conditions, faint ambient music can be heard. This audio is inconsistent, has no identifiable source, and appears unrelated to intercom behavior. The significance of this event remains unknown.