The Unmaker is a weapon in Doom 64 of demonic origin, inscribed with a pentagram and made up of parts of the spine and rib bones of a demon. It fires powerful red lasers by consuming cells as ammo. The original name of the weapon is unknown and unverifiable; the community-given name "Unmaker" has long been applied to the weapon due to analogy with a similar concept in the Doom Bible. This name was made official by the 2020 re-release of the game, in an achievement.
The concept and mechanics of the Unmaker are strongly referenced by a weapon in Doom Eternal known as the Unmaykr. The nature of the relationship of the two weapons is unclear; the Unmaykr fires three bolts in a similar manner to the fully powered Unmaker, and uses firing sounds from the Doom 64 weapon when the classic weapon sounds option is enabled.
The Unmaker is the only new weapon in Doom 64. It begins as the second strongest weapon behind the BFG9000, with slightly better damage but a slower firing rate than the plasma gun. It is especially rare and can only be found in a few levels; chronologically it can first be located in the secret level MAP29: Outpost Omega, with another opportunity to collect it not occuring until MAP12: Altar of Pain. In The Lost Levels expansion, the Unmaker can only be found on MAP39: Final Judgement.
Uniquely amongst Doom weaponry, the Unmaker can be upgraded by finding the three mysterious and well-protected Demon Key artifacts:
- The first one lowers the firing pause between each laser from 8 tics (0.266 seconds) to 5 tics (0.166 seconds).
- The second key adds a second laser, raises the ammo usage to 2 cells per shot, and further decreases the firing pause to 4 tics (0.133 seconds).
- The third one makes the weapon fire three simultaneous lasers and raises the ammo usage to 3 cells per shot.
Each laser of the Unmaker is a hitscan attack that can do between 10 and 80 damage (10x+10 where x is a random value of 0 to 7). The red laser seen while shooting is actually just a visual effect representing the calculated hitscan trajectory from the attack's origin point to where the impact calculation lands. This means that the red lasers are inconsequential in the calculation of damage and do not interact with actors. This may give the impression that the lasers pierce through enemies, when in reality they simply follow a precalculated trajectory. The damage of an individual laser attack is not affected by artifact count. The laser hitscan calculation has a maximum distance of 4096 map units, and the origin point of the attack is 40 units over the player's current z-position.
Like every hitscan attack in the game, each successful hit has an independent chance of triggering a monster's pain state, with the fully equipped Unmaker critically increasing this chance due to being able of causing multiple simultaneous impacts on a target in rapid succession. This carries the consequence of it being able to cause an almost permanent pain-stun on any monster in the game, allowing the player to dispatch the Cyberdemon and even the mighty Mother Demon or Sister Resurrector with impunity. While the BFG can dole out higher damage and strike more targets at a single time, the Unmaker arguably surpasses it in utility in the late game when it is at its full strength, strong enemies come in singles or small groups, and cell ammo is at a premium.
The weapon is never officially named within the original game itself, and is kept a secret by the instruction manual. The Unmaker weapon sprite is named LASR and the pick-up sprite is named LSGR. It is likewise referred to by several unofficial or tentative names in pre-release previews, walkthroughs, reviews, ads, and the game's official strategy guide. These include the following:
- "alien gun"
- "alien laser" (a name also referenced by level designer Tim Heydelaar)
- "alien weapon"
- "crazy laser"
- "demon laser"
- "gros laser qui tue" (English: "big fucking laser", literally "big laser that kills")
- "high powered laser"
- "laser" 
- "laser action machine gun"
- "laser beam"
- "laser cannon"
- "laser gun"
- "laser rifle"
- "laser weapon"
When the weapon is collected, the marine simply exclaims, "What the !@#%* is this!"
The 2020 re-release officially uses the name Unmaker for the weapon in achievement descriptions and promotional materials.
The Doom Bible concept for the Unmaker was originally intended to be in the pre-planned commercial sequel to Doom itself. According to the Doom Bible, the Unmaker was intended to be a "demon-tech weapon that hurts pure demons a lot, demon-humans very little, tech demons some. Made of demon bones. (...) The Dark Claw and Unmaker feed on human souls. Killing possessed humans or hellslaves allows the weapons to feed".
As a weapon in the Doom alphas, the Unmaker appears only in Doom v0.2, and there only in the form of two unused lumps for the game's helmet visor HUD: WBOXUNM contains the name of the weapon, and WPICUNM contains a silhouette. After this, there are no further references to the weapon concept. It was meant by Tom Hall to occur as a new weapon in the commercial sequel to Doom and not in the first game itself, which is likely why its concept was quickly dropped.
- The reaper in Doom (2016) has a charged attack which fires a similar laser-like beam of Hell energy.
- One pre-release screenshot shows what is sometimes presumed to be an early version of the Unmaker. The publication itself mentions there could be "possibly new weapons and monsters" in Doom 64. Tim Heydelaar instead believes this picture is of an early rocket launcher model.
- Original source graphics for the Doom v0.2 HUD, as released by John Romero in 2015. The Unmaker icon begins in column 30 at row 14, and resembles a skull and spine with various bony projections extending from it which form vague grips and a stock.
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