Lazarus Labs

Lazarus Labs is the ninth level of DOOM, with the mission involving the map called simply "Lazarus".

Penetrating into the heart of the initial demonic invasion of Mars, your mission is simple: find the Argent Accumulator so that you can get back to Hell and reclaim the Crucible. Hell's strongest minions on Mars will be standing between you and the way back into Hell, but they're nothing you should not be able to handle.

There are nine secrets, four Elite Guards, one Field Drone, one Argent Cell, and two Rune Trials located in this level. The Cyberdemon is encountered at the end of the level as a boss monster, and must be defeated twice to continue. The Spectre also makes its debut, in the level's Rune Trials.

Lazarus Labs
''The Lazarus Labs is a sub-division of the Advanced Research Complex, and is also accessible at the highest clearance levels. Located deep underground to prevent infiltration (or exfiltration), the Lazarus Labs are home to the longest-serving and most dedicated UAC staff. Information regarding the Lazarus Project is hard to come by as its members are highly secretive and well disciplined. What is known is that any cross-dimensional anomalies, entities, or artifacts are immediately sent to the Lazarus Labs for research, and are never seen again. However, promotion to the Lazarus Project is seen as a badge of honor among the UAC staff - despite not knowing exactly what their work will entail.''

An Important Message
''Fellow disciple, this message has been sent to you in recognition of your service to the Lazarus Project. I am Olivia Pierce. You have been granted the highest level of clearance we allow in the Lazarus Project, and as such you are expected to partake in all rituals, sacrifices and vivisection programs (both demon and human) as requested - whether as a practitioner of the dark arts or a patient of a cleansing. As we work tirelessly to open the gates to Hell, remember our mantra: "The science will cleanse us".''

''Our recent expedition to the Great Steppe resulted in the retrieval of new tablets which will help us further decode the Helix Stone. I must again reiterate the importance of fully decoding this stone. The scriptures tell us that it holds the key to both realizing our future and destroying us - so we must know it before the enemy. The enemy will come and we must be ready. While we are decoding the latest artifacts and relics, there will be no rest, no leave and no sleep. We must succeed. Our lives mean nothing. Opening the gates is everything.''

Challenges

 * Variety is the Spice of Death II - Perform 5 different glory kills on Possessed Soldiers.
 * Thread the Needle - Kill 8 demons with a single shot. (Note: BFG kills do count as one shot.)
 * Time Well Spent - Play a game of Demon Destruction. (Note: this is a Classic Doom-themed version of Bejeweled / Candy Crush found on a computer in-game.)

Characters

 * Samuel Hayden
 * Olivia Pierce (holo-recording)
 * UAC Spokesperson
 * UAC Facility Voice
 * Dark Lord (voice)
 * VEGA

New Weapons

 * Siphon Grenade

Trivia

 * This level is split into two parts, possibly to put less stress on the hardware of console versions.
 * If using the Saving Throw rune, if it's already been activated, the rune will reset after the cutscene that triggers with the Helix Stone. This would only happen if re-playing the level, since normally the player encounters the Helix Stone before the Saving Throw rune stone.
 * The player gets several warnings of his impending encounter with the Cyberdemon. In several places, he hears an ominous thumping off in the distance; shortly thereafter he finds a Data Log that depicts it (usually he only obtains one for a specific demon after killing the monster in question, and not from a pickup); and finally there is the empty cell where the Cyberdemon was kept where he finds the Automap.
 * One recording finally identifies the whispering contrabass voice that narrates the Doom Slayer's testaments and announces "He's here!" at the beginning of Kadingir Sanctum: a lord of Hell that Olivia Pierce has been collaborating with.
 * One recorded hologram depicts a human sacrifice. This may indicate that the Possessed became the way they did though their own free will, by joining Olivia Pierce's satanic cult, and that those UAC employees who did not join were killed instead of turned by the Lazarus Wave.
 * The Soul Cube from Doom 3 may also be found in the room with the Demon Destruction game.
 * Lazarus Labs appears to be more or less the equivalent of Delta Labs in Doom 3. Gory experiments and the remains of demonic and human specimens may be found all over the facility, while the lower section of the labs includes a satanic chapel where human sacrifices took place, all of this making it by far the most frightening and disturbing level in the game (including the Hell levels). At one spot, the player even closes the Hell portal Olivia used to invite in the demons, although it is actually treated as a minor plot point, in comparison to the fight with the Cyberdemon. Presumably, this Hell portal is unsuitable for Doomguy's upcoming quest in Titan's Realm, leading to a completely different section of Hell.