YEY! I finally managed to do this, though the newest beta's weapon mods did help, as they allowed me to get defensive some defensive traits in place of speed and reload traits. Perhaps I could have avoided all of Cybies missiles with some additional levels in Hellrunner.
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DoomRL (v.0.9.8.5 Beta 2) roguelike post-mortem character dump
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Fingerzam, level 8 Cacodemon Lieutenant, defeated the Cyberdemon
on level 25 of the Phobos base.
He survived 91122 turns and scored 42741 points.
He didn't like it too rough.
He killed 278 out of 278 hellspawn. (100%)
This ass-kicking marine killed all of them!
He was an Angel of Marksmanship!
He found the Phobos Arena.
He stormed the Chained Court.
He fought on Hell's Arena.
He became a champion of Hell's Arena!
-- Statistics ------------------------------------------------
Health 51/70 Experience 27036/8
ToHit +0 ToDmg Ranged +0 ToDmg Melee +0
-- Traits ----------------------------------------------------
Ironman (Level 2)
Finesse (Level 1)
Hellrunner (Level 1)
Son of a gun (Level 3)
Dualgunner (Level 1)
-- Equipment -------------------------------------------------
[a] [ Armor ] red armor [4/4] (51%)
[b] [ Weapon ] advanced pistol (2d6) [8/13] (D2R3S2M3)
[c] [ Boots ] plasteel boots [8/8] (92%)
[d] [ Prepared ] pistol (2d4) [1/6]
-- Inventory -------------------------------------------------
[a] blue armor [2/2] (79%)
[b] blue armor [2/2] (100%)
[c] blue armor [2/2] (100%)
[d] red armor [4/4] (50%)
[e] red armor [4/4] (100%)
[f] red armor [4/4] (100%)
[g] red armor [4/4] (100%)
[h] 10mm ammo (x33)
[i] 10mm ammo (x100)
[j] 10mm ammo (x100)
[k] large med-pack
[l] large med-pack
[m] large med-pack
[n] large med-pack
[o] large med-pack
[p] large med-pack
[q] phase device
-- Kills -----------------------------------------------------
32 former humans
21 former sergeants
13 former captains
15 imps
31 demons
31 lost souls
33 cacodemons
7 barons of hell
1 Cyberdemon
8 hell knights
29 arachnotrons
4 former commandos
8 pain elementals
4 arch-viles
-- History ---------------------------------------------------
He started his journey on the suface of Phobos.
On level 2 he battled through the complex.
Afterwards he fought on Hell's Arena.
On level 3 he battled through the complex.
On level 4 he battled through the complex.
On level 5 he battled through the complex.
He then stormed the Chained Court.
On level 6 he battled through the complex.
On level 7 he found a hellish city.
On level 8 he found hellish caves.
On level 9 he found hellish caves.
On level 10 he battled through the complex.
On level 11 he battled through the complex.
On level 12 he battled through the complex.
On level 13 he found hellish caves.
On level 14 he found a hellish city.
On level 15 he found a hellish city.
On level 16 he found a hellish city.
On level 17 he found hellish caves.
On level 18 he battled through the complex.
On level 19 he battled through a maze of rooms.
On level 20 he found hellish caves.
On level 21 he found hellish caves.
On level 22 he battled through a maze of rooms.
On level 23 he battled through a maze of rooms.
On level 24 he battled through a maze of rooms.
Then at last he found the Phobos Arena.
There he finally defeated the Cyberdemon.
-- Messages --------------------------------------------------
The Cyberdemon loses blood.
You are hit!
You reload the pistol with 10mm ammo. You reload the pistol with 10mm ammo.
The Cyberdemon fires! You hear an explosion!
Fire -- Choose target... The missile hits the Cyberdemon. The Cyberdemon is
bleeding! The missile hits the Cyberdemon.
Fire -- Choose target... The missile hits the Cyberdemon. The missile hits
the Cyberdemon.
Fire -- Choose target... The missile hits the Cyberdemon. The missile hits
the Cyberdemon.
Fire -- Choose target... The missile hits the Cyberdemon. The missile hits
the Cyberdemon. The Cyberdemon reloads his rocket launcher. The
Cyberdemon loses blood.
Fire -- Choose target... The missile hits the Cyberdemon. The Cyberdemon
dies. Congratulations! You defeated the Cyberdemon! Press <Enter>
-- General ---------------------------------------------------
Before him 61 brave souls have ventured into Phobos:
59 of those were killed.
1 of those was killed by something unknown.
And 1 couldn't handle the stress and commited a stupid suicide.
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I'll explain the weapon mods in my pistol here:
D2 - 2 damage mods, each increasing the damage die by one.
R3 - 3 reload mods, resulting in 0.6^3 reloading time
S2 - 2 speed mods, each giving 10% boost, so 2 equals rapid
M3 - 3 magazine mods, I don't know how these are calculated, but I got my clip increased by 2 for the first two, and the last one gave 3.
Trait order: SoaG(3) --> Dualgunner(1) --> Finesse(1) --> Ironman(1) --> Hellrunner(1) --> Ironman(2)
My fight against Cybie went a lot better than my last try. Last time Cybie spawned allmost right next to me, this time he was further away and I could get some room between me and the walls, so that dodged missiles wouldn't do any damage. I shot him 3 times after he reloaded and just to be safe startet dodging after that, and then started shooting again. Got some cover for reloading, cause my secondary pistol takes way too long to reload (ofcourse I could have just reloaded my main gun and forget about the second one).
Spent 1 phase device when Cybie destroyed stuff from around me to get more cover and 1 med-pack when I was on half health just to be sure, since I have bad memories about Cybie doing something like 35 damage with a single missile.