Well, I had a REALLY lucky first try on Nightmare, although I still didn't win. I studied the strategies here and they made a big difference. I agree that Angel of Haste is a requirement. Also, you have to farm the first level until you at least make level 9.
I made it all the way to Cybie. I made it there by some luck - I found an Invulnerability globe that helped me through two levels. I also picked up a Phase Device that helped me past the Mortuary, which gave me two sets of red armor. I ended up facying the CD with 4 large medipacks, 2 red armors, 1 plasma rifle with no reloads, and 2 chainguns with tons of ammo (I was originally just wielding two chainguns so I could swap when I ran out of ammo).
I hardly ever fired a shot once I left the starting level. I picked off the occasional baddie, but most of all I just ran around looking for any set of down-stairs.
The end result was I had the CD at Mortally Wounded for a few turns with my chaingun, but I just couldn't finish him off before he killed me.
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DoomRL (v.0.9.8.5 Beta 3) roguelike post-mortem character dump
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Styro-AoH, level 11 Cacodemon Captain, killed by a Cyberdemon
on level 25 of the Phobos base.
He survived 51186 turns and scored 223052 points.
He opposed the Nightmare!
He killed 927 out of 1229 hellspawn. (75%)
He was an Angel of Haste!
He found the Phobos Arena.
He faced The Wall.
He was caught in the Mortuary!
-- Statistics ------------------------------------------------
Health -4/80 Experience 51600/11
ToHit +3 ToDmg Ranged +0 ToDmg Melee +0
-- Traits ----------------------------------------------------
Ironman (Level 3)
Hellrunner (Level 3)
Tough as nails (Level 3)
Eagle Eye (Level 1)
Badass (Level 1)
Iro->Iro->Iro->TaN->TaN->HR->TaN->HR->HR->Bad->EE->
-- Equipment -------------------------------------------------
[a] [ Armor ] nothing
[b] [ Weapon ] chaingun (1d6)x5 [40/50]
[c] [ Boots ] steel boots [2/2] (100%)
[d] [ Prepared ] plasma rifle (1d8)x8 [0/40]
-- Inventory -------------------------------------------------
[a] chaingun (1d6)x5 [50/50]
[b] 10mm ammo (x100)
[c] 10mm ammo (x100)
[d] 10mm ammo (x100)
[e] 10mm ammo (x100)
[f] 10mm ammo (x100)
[g] 10mm ammo (x100)
[h] 10mm ammo (x100)
[i] 10mm ammo (x100)
[j] 10mm ammo (x100)
[k] 10mm ammo (x100)
[l] 10mm ammo (x100)
[m] rocket (x6)
-- Kills -----------------------------------------------------
135 former humans
15 former sergeants
230 former captains
184 imps
333 demons
6 lost souls
2 cacodemons
2 hell knights
-- History ---------------------------------------------------
On level 10 he witnessed the Wall.
Not knowing what to do, he left.
On level 22 he was foolish enough to enter the Mortuary!
He managed to escape from the Mortuary!
Then at last he found Phobos Arena!
On level 25 he finally was killed by a Cyberdemon.
-- Messages --------------------------------------------------
Fire -- Choose target... The missile hits the Cyberdemon. The missile hits
the Cyberdemon. The missile hits the Cyberdemon. The missile hits the
Cyberdemon. The missile hits the Cyberdemon. The Cyberdemon is bleeding!
You lose blood! The Cyberdemon hits you. The Cyberdemon loses blood.
Fire -- Choose target... The missile hits the Cyberdemon. The missile hits
the Cyberdemon. The missile hits the Cyberdemon. The missile hits the
Cyberdemon. The missile hits the Cyberdemon. You lose blood! The Cyberdemon
hits you. The Cyberdemon loses blood.
You reload the chaingun with 10mm ammo. You lose blood! The Cyberdemon
misses you. The Cyberdemon stops bleeding. The Cyberdemon hits you.
The Cyberdemon hits you.
Fire -- Choose target... The missile hits the Cyberdemon. The missile hits
the Cyberdemon. The missile hits the Cyberdemon. The missile hits the
Cyberdemon. The missile hits the Cyberdemon. You lose blood! The Cyberdemon
hits you. You die!...
-- General ---------------------------------------------------
Before him 85 brave souls have ventured into Phobos:
76 of those were killed.
1 of those was killed by something unknown.
1 didn't read the thermonuclear bomb manual.
Some rumours though, say that the Cyberdemon was killed already!
Is he immortal? 7 souls claim to have killed him...
1 sacrificed itself for the good of mankind.
6 killed the bastard and survived.
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