D5
- Template
- Place
- Status
- Canon
- Kind
- Level
- Parent
- Military Base
1. Summary
D5 — Advanced Biological Research and Containment Level.
2. History
Construction of Level D5 began on February 4, 1975, and the facility became operational on August 11, 1978. D5 was established because the containment systems of D3 had become inadequate for increasingly dangerous biological research. Conceived as a deeper, more secure extension of the installation's experimental programs, D5 housed highly infectious pathogens, experimental viruses, human biological enhancement programs, advanced organ transplantation, artificial and modified organs, and attempts to create biological super-soldiers. Its scientists also investigated radical tissue regeneration, organ rejuvenation, cancer-based experimental treatments, biological stasis, cross-species transplantation, and the artificial creation of biological brains. Many of these experiments resulted in catastrophic deformities, unstable organisms, or complete failure. Alongside its containment programs, D5 housed the facility's neuroscience laboratories, devoted to perception, memory, consciousness, and behavioral modification, whose work D6 later drew upon.
See: Timeline › Master Timeline
See: Places › D6
3. Function and Contents
Throughout D5, the protagonist encounters evidence of extreme biological experimentation, including grotesquely altered human bodies, hybridized animal specimens, and experimental organisms that survived the facility's abandonment. Some subjects remain preserved inside stasis chambers, while others have escaped containment and wander through isolated sections of the level. One particularly disturbing subject, horribly deformed by an unsuccessful regenerative experiment, remains suspended in stasis despite being biologically beyond recovery. D5 is also the origin of the stasis technology later obtained by the protagonist's father. Certain corridors and laboratories remain dangerously contaminated, requiring the protagonist to seek assistance from an artificial intelligence to activate the appropriate decontamination systems before proceeding.
Among the level's most unusual experiments is Brain, a preserved human brain maintained in a life-support vessel and connected to an artificial experiential environment. Taken without consent from the body of a deceased, destitute individual whose human life had been marked by profound suffering, Brain now experiences an existence of extraordinary pleasure. Optional conversations explore Robert Nozick's experience machine, the nature of suffering and happiness, the possibility of simulated reality, and the uncertainty of death. Brain's questions gradually challenge the protagonist's confidence in the reality of his own existence. His attitude, and what the player can decide about him, are described on his page. See: Characters › Brain.
4. Architecture and Style
D5 is a vast, heavily fortified underground biological research complex designed during the 1970s and continuously modernized until 1999. Its architectural identity differs sharply from D3's comparatively bright, hospital-like laboratories. D5 features a darker, more oppressive aesthetic, combining charcoal-gray and dark metallic surfaces, muted industrial colors, reinforced containment chambers, hermetically sealed laboratories, heavy security doors, and sophisticated environmental control systems. Advanced biological equipment, observation windows, stasis chambers, and experimental containment vessels give portions of the facility an almost alien appearance, despite their human technological origins.
D5 is extraordinarily well preserved. Most corridors are immaculate, equipment remains functional, and laboratories appear almost ready to receive their researchers. Empty offices, illuminated passageways, active computer terminals, and perfectly maintained rooms create a profoundly unsettling liminal atmosphere: the facility looks occupied, yet no human personnel remain. Scattered signs of the 1999 catastrophe—damaged containment chambers, abandoned equipment, occasional destroyed rooms, and traces of armed confrontations—interrupt this deceptive normality. The resulting atmosphere combines the sterility of advanced biological research, the oppressive darkness of a secret military installation, and the disturbing emptiness of a place that seems to be waiting for its inhabitants to return.
5. Security and Access
Extensive ventilation infrastructure, airlocks, sterilization systems, isolated laboratory sectors, specialized waste-processing facilities, and a large industrial incinerator support the level's hazardous biological operations. Autonomous robots, manufactured in the same standardized series used throughout D4, patrol corridors and maintain the facility's infrastructure in greater numbers. Lethal supersoldier robots, the heavily armored robotic soldiers developed in D4, guard the approach toward D6 and killed scientists who tried to pass. The base's experimental fusion reactor, in its protected complex beside D3, powered its lighting, computers and research systems until the 1999 evacuation, when it was shut down; since then its robotic maintenance, security and containment systems have run on the base's experimental battery system, long after the personnel evacuation.
See: Enemies › SQUAD Unit
6. Connections
The approach to the elevator from D4 toward D5 was wrecked during an earlier battle.
See: Places › D4
D5 ↔ A4: containment-related railway.
D5 is also linked to D3, whose page describes that connection.
See: Places › D3
See: Places › A4 — Hazardous Materials And Disposal Complex
The approach toward D6 is guarded by lethal supersoldier robots. Six SQUAD Units remain active in D5, alongside Patrol Robots and Flesh Nests; Broken Survivors do not inhabit this level. See: Enemies › SQUAD Unit.
See: Places › D6
7. Concept Image
D5 — Advanced Biological Research and Containment Level concept, kept in the game repository at environments/military_base/children/d5/concept.png
8. Open Questions
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