I do when I can, but even good layouts for N! floors can be dangerous to a low level doomguy without a ridiculous damage output - less good layouts are death sentences. Here's a mortem from a failed run where I had to stop in what looked like a safe room to try permakilling some stuff so I could get to the stairs:
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DoomRL (0.9.9.7) roguelike post-mortem character dump
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Nathan, level 5 Cyberdemon Lt. General Scout,
was bruised by a baron of hell on level 4 of Hell.
He survived 247662 turns and scored 47384 points.
He played for 1 hour, 37 minutes and 56 seconds.
He opposed the Nightmare!
He killed 1241 out of 1349 hellspawn. (91%)
He held his right to remain violent.
He was an Angel of Shotgunnery!
He was also an Angel of Overconfidence!
-- Special levels --------------------------------------------
Levels generated : 4
Levels visited : 1
Levels completed : 0
-- Awards ----------------------------------------------------
UAC Star (gold cluster)
-- Graveyard -------------------------------------------------
###########################################################
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#######...M########..===.==.....===.=.=======.............#
#######.............========.#./.===V===.......#####..==...
#..###..==......+..========..X..#=======.#####./...#.====.#
#....hi===.i...}ii========......#.======.#...#.#...#.====.#
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##..======.^#...#...B.===.\|......=====..#...#.#.V.#.====.#
#....i..i...#...#..h#...O.......===......#...#.#####..==.R#
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###########################################################
-- Statistics ------------------------------------------------
Health 0/50 Experience 7904/5
ToHit Ranged +0 ToHit Melee +0 ToDmg Ranged +0 ToDmg Melee +0
-- Traits ----------------------------------------------------
Class : Scout
Hellrunner (Level 1)
Reloader (Level 2)
Intuition (Level 2)
Int->Int->HR->Rel->Rel->
-- Equipment -------------------------------------------------
[a] [ Armor ] Medical Powerarmor [0/4] (0%)
[b] [ Weapon ] assault shotgun (7d3) [1/6] (T1)
[c] [ Boots ] protective boots [2/2] (100%)
[d] [ Prepared ] nothing
-- Inventory -------------------------------------------------
[a] shotgun (8d3) [1/1]
[b] shotgun shell (x50)
[c] shotgun shell (x50)
[d] shotgun shell (x50)
[e] shotgun shell (x50)
[f] shotgun shell (x50)
[g] shotgun shell (x50)
[h] shotgun shell (x50)
[i] shotgun shell (x50)
[j] shotgun shell (x50)
[k] shotgun shell (x50)
[l] shotgun shell (x50)
[m] shotgun shell (x50)
[n] shotgun shell (x50)
[o] shotgun shell (x25)
[p] shotgun shell (x50)
[q] large med-pack
[r] large med-pack
[s] phase device
[t] thermonuclear bomb
[u] shockwave pack
-- Resistances -----------------------------------------------
Acid - internal 0% torso 0% feet 25%
-- Kills -----------------------------------------------------
20 former humans
1147 former sergeants
8 former captains
4 imps
1 demon
21 lost souls
5 former commandos
2 pain elementals
29 revenants
4 arch-viles
-- History ---------------------------------------------------
On level 3 he entered the Vaults.
He came, he saw, but he left.
On level 4 he found the Medical Powerarmor!
On level 4 he finally was bruised by a baron of hell.
-- Messages --------------------------------------------------
The arch-vile raises his arms!
Fire -- Choose target...
You see : an arch-vile (severely wounded) | lava | [ m ]ore
Your weapon is empty.
Your weapon is empty.
You reload the assault shotgun. You are engulfed in flames! Your Medical
Powerarmor is damaged!
You reload the assault shotgun.
Fire -- Choose target...
You see : an arch-vile (severely wounded) | lava | [ m ]ore
The arch-vile raises his arms!
You reload the assault shotgun.
Fire -- Choose target...
You see : an arch-vile (mortally wounded) | lava | [ m ]ore
You are engulfed in flames! Your Medical Powerarmor is damaged! You dodge!
Your Medical Powerarmor is damaged! You die!... Press <Enter>...
-- General ---------------------------------------------------
2117 brave souls have ventured into Phobos:
1931 of those were killed.
6 of those were killed by something unknown.
39 didn't read the thermonuclear bomb manual.
And 105 couldn't handle the stress and committed a stupid suicide.
36 souls destroyed the Mastermind...
6 sacrificed itself for the good of mankind.
30 killed the bitch and survived.
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This was after my initial farm floor, where I slaughtered a former sergeant hundreds of times for killcount and ammunition. I couldn't have been better prepared for a stairdive. But then in that floor, I got caught in a room by an archvile who shredded a wall and then somehow popped a barrel outside my vision(I think it was behind the wall that was still there, somehow) for an unexpected death.
Trying to permakill every floor is not something I'm capable of at my own skill level without unbelievable luck in level generation. I saw your Elite and Veteran Diamond badge mortem, and it's clear you have the skill level for this, but without it, this is the only strategy that's remotely viable for me.