Doom 3 (v1.3.1) | [gog]

: Set two years later, a new protagonist (another Marine) is sent back to the abandoned Mars base to investigate a mysterious beacon, leading to a second confrontation with Dr. Betruger (now a demonic entity) and the recovery of the "Artifact." -60% DOOM 3 on GOG.com

The core conflict revolves around . Dr. Betruger’s experiments accidentally (and intentionally) open a gateway to Hell . A massive shockwave ripples through the base, instantly transforming most of the UAC staff into mindless zombies and allowing demonic entities to invade the facility. Key Plot Points DOOM 3 (v1.3.1) [GOG]

You play as a newly arrived assigned to security. The atmosphere is tense; the base is plagued by mechanical failures, "ghostly" sightings, and a workforce on the edge of a nervous breakdown. Tensions are high between the base administrator, Elliott Swann , and the lead scientist, Dr. Malcolm Betruger , over mysterious experiments conducted in the Delta Labs. The Inciting Incident : Set two years later, a new protagonist

: Unlike the "run-and-gun" style of other entries, the DOOM 3 story emphasizes isolation and darkness. The atmosphere is tense; the base is plagued

: The Marine must travel into the heart of Hell, defeat the Cyberdemon guarding the primary "Hell Hole," and use the Soul Cube to close the gateway. Version 1.3.1 [GOG] Specifics

: You eventually learn that Dr. Betruger has defected to the side of Hell, orchestrating the invasion in exchange for power.