I set out trying to get a conqueror win, but I forgot about the cathedral so I threw away my chainsaw. Sad. On the plus side, by the time I realized that I found the napalm launcher, so I decided to dedicate this run to the Scavenger Diamond badge instead.
Strategy was simple: I stocked up on rockets and painted every single tile of the Vaults with lava. I only actually found one non-homing phase device, but it didn't matter because I had a near-100% chance of success (the only non-lava tile outside the center vault was the stairs). It took something around 90 rockets to do so (fortunately the level spawns 48 plus whatever the revenants drop). I popped an envirosuit pack right after the teleport for safety (thank you technician bonus), and only lost ~30% health to the ambush inside. I kept the arena master's staff until then just in case though.
After that, I found a nano mod and tackled limbo just for the guaranteed asssault shotgun+power pack to finish a nano shotgun (finishing another platinum badge--only assembly left is the stupid BFG). In the end, I did every level except the cathedral.
The combination of cerebus boots, napalm launcher and a double-sniper chaingun (with intuition) is loads of fun. All three of those items were surprisingly useful even on their own, I was especially imrpessed by the boots (I probably wouldn't have risked my run on Limbo without them).
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 DoomRL (0.9.9.7) roguelike post-mortem character dump
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 Dave, level 16 Arch-Vile Br. General Technician,
 nuked the Mastermind at the Hell Fortress.
 He survived 223816 turns and scored 410605 points. 
 He played for 9 hours, 16 minutes and 31 seconds. 
 He was a man of Ultra-Violence!
 He killed 1335 out of 1335 hellspawn. (100%)
 This ass-kicking marine killed all of them!
 He saved himself 3 times.
-- Special levels --------------------------------------------
  Levels generated : 11
  Levels visited   : 10
  Levels completed : 10
-- Awards ----------------------------------------------------
  Medal of Prejudice
  UAC Star (gold cluster)
  Aurora Medallion
  Grim Reaper's Badge
  Hell Armorer Badge
  Hell Champion Medal
  Technician Platinum Badge
  Scavenger Platinum Badge
  Scavenger Diamond Badge
-- Graveyard -------------------------------------------------
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  ###########################################################
-- Statistics ------------------------------------------------
  Health 52/80   Experience 124579/16
  ToHit Ranged +4  ToHit Melee +4  ToDmg Ranged +0  ToDmg Melee +0
-- Traits ----------------------------------------------------
  Class : Technician
    Ironman          (Level 3)
    Finesse          (Level 1)
    Hellrunner       (Level 2)
    Tough as nails   (Level 1)
    Eagle Eye        (Level 2)
    Juggler          (Level 1)
    Dodgemaster      (Level 1)
    Intuition        (Level 2)
    Whizkid          (Level 2)
    Scavenger        (Level 1)
  EE->EE->Int->Int->WK->WK->HR->MSc->Fin->Jug->HR->DM->Iro->Iro->TaN->Iro->
-- Equipment -------------------------------------------------
    [a] [ Armor      ]   red armor [6/6] (69%) (AP)
    [b] [ Weapon     ]   tactical rocket launcher (6d6) [2/5] (T1)
    [c] [ Boots      ]   protective boots [2/2] (100%) (A)
    [d] [ Prepared   ]   nothing
-- Inventory -------------------------------------------------
    [a] chaingun (1d7)x4 [40/40] (A1P1S2)
    [b] hyperblaster (2d4)x3 [13/40] (T1)
    [c] nano assault shotgun (5d3) (P1)
    [d] napalm launcher (7d7) [1/1] (S2)
    [e] BFG 9000 (10d6) [20/100] (T1)
    [f] Angelic Armor [7/7] (95%)
    [g] rocket (x8)
    [h] power cell (x70)
    [i] power cell (x70)
    [j] large med-pack
    [k] large med-pack
    [l] large med-pack
    [m] large med-pack
    [n] large med-pack
    [o] large med-pack
    [p] lava element
    [q] cerberus steel boots [0/0] (100%) (A)
    [r] rocket box (x9)
-- Resistances -----------------------------------------------
    Bullet     - internal 60%   torso 60%   feet 60%  
    Melee      - internal 60%   torso 60%   feet 60%  
    Shrapnel   - internal 60%   torso 60%   feet 60%  
    Acid       - internal 60%   torso 60%   feet 85%  
    Fire       - internal 60%   torso 85%   feet 60%  
    Plasma     - internal 60%   torso 60%   feet 60%  
-- Kills -----------------------------------------------------
    97 former humans
    88 former sergeants
    48 former captains
    193 imps
    77 demons
    387 lost souls
    46 cacodemons
    68 hell knights
    89 barons of hell
    68 arachnotrons
    12 former commandos
    32 pain elementals
    28 revenants
    29 mancubi
    33 arch-viles
    3 nightmare imps
    11 nightmare cacodemons
    17 nightmare demons
    2 bruiser brothers
    1 shambler
    1 lava elemental
    1 agony elemental
    1 Cyberdemon
    1 Spider Mastermind
    1 John Carmack
    1 Arena Master
-- History ---------------------------------------------------
  He started his journey on the surface of Phobos.
  On level 2 he entered Hell's Arena.
  He left the Arena as a champion!
  On level 5 he stormed the Chained Court.
  On level 5 he found the Arena Master's Staff!
  He defeated the Hell Arena Master!
  On level 6 he assembled a tactical shotgun!
  On level 7 he sneaked into the Phobos Lab.
  He broke through the lab.
  On level 8 he encountered the Phobos Anomaly.
  On level 9 he entered Hell's Armory.
  On level 9 he found the Revenant's Launcher!
  On level 9 he assembled a cerberus boots!
  He destroyed the evil within and reaped the rewards!
  On level 11 he arrived at the Containment Area.
  He emerged from the Containment Area victorious!
  On level 12 he assembled a tactical rocket launcher!
  On level 12 he assembled a hyperblaster!
  On level 12 he romped upon the Abyssal Plains.
  He slaughtered the beasts living there.
  On level 14 he ventured into the Spider's Lair.
  He cleared the Lair, kickin' serious spider ass!
  On level 16 he found the Tower of Babel!
  On level 19 he found the Mega Buster!
  On level 19 he entered the Vaults.
  On level 19 he found the Acid Spitter!
  He managed to clear the Vaults completely!
  On level 20 he was foolish enough to enter Limbo!
  On level 20 he assembled a nano-shrapnel!
  On level 20 he found the Angelic Armor!
  He managed to clear Limbo from evil!
  On level 22 he arrived at Mt. Erebus.
  On level 22 he found the Medical Powerarmor!
  He managed to raise Mt. Erebus completely!
  Then at last he found Dis!
  He overloaded a nuclear BFG 9000 on level 24!
  He defeated the Mastermind and found the TRUE EVIL!
  Then finally in Hell itself, he killed the final EVIL.
-- Messages -------------------------------------------------- 
 You see : John Carmack (almost dead) | pool of blood | [ m ]ore 
 The missile hits John Carmack. John Carmack reloads his rocket launcher. 
 You use a hatred skull. You feel like a killing machine! You need to taste 
 blood! 
 Unknown command. Press "?" for help. 
 Fire -- Choose target... 
 You see : John Carmack (almost dead) | pool of blood | [ m ]ore 
 Targeting canceled. 
 You need to taste blood! 
 You need to taste blood! 
 You dodge! You need to taste blood! 
 Fire -- Choose target... 
 You see : John Carmack (almost dead) | pool of blood | [ m ]ore 
 The missile hits John Carmack. John Carmack dies. Congratulations! You 
 defeated John Carmack! Press <Enter>... 
 You feel relatively safe now. 
-- General --------------------------------------------------- 
 116 brave souls have ventured into Phobos:
 75 of those were killed.
 2 didn't read the thermonuclear bomb manual.
 And 3 couldn't handle the stress and committed a stupid suicide.
 36 souls destroyed the Mastermind...
 1 sacrificed itself for the good of mankind.
 28 killed the bitch and survived.
 7 showed that it can outsmart Hell itself.
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