Delta Labs, otherwise known as the Delta Complex, is one of the prominent locales in Doom 3. It is also one of the hardest parts of the game as the player fights more than a hundred demons, suffers from hallucinations and must unlock several lockers. The lack of cutscenes makes gameplay constant, though Dr. Betruger constantly addresses the player and the demons over the loudspeakers. In addition, the main portal is located in the Delta Labs. The player returns to Delta Labs after retrieving the Soul Cube to find the area in ruins and coated in demonic growth.