So, umm, images:
#68 Zarathustra PN19 Heavy Machine Gun, #66 Ayanami Avenger Automatic Rifle, #67 Ayanami MP, #72 Serrano Model 12 Revolver, #73 M14A3 Designated Marksman Rifle
#74 Zarathustra PMR26 Marksman Rifle, #75 Standish GP-4 Top-Loading Grenade Launcher, scrapped skeletonized Ayanami-S design (#76)
#63 Marduk Model 11 Lever-Action Rifle/Shotgun, #64 Ayanami-DSK Neostead-type Shotgun, #65 Will of the God-Ender Atlas, #66 Ayanami Avenger, #67 Ayanami MP, scrapped turret weapon, #68 Zarathustra PN19, censored obscene gun, Zarathustra RP22 Assault Rifle, Zarathustra PPM99 Submachine Gun
Nishimura Seven Battle Rifle (The Trooper), #17 Legend Armory "Trinity" Triple-Barrelled 8-Gauge Shotgun, #18 Jotun M19 Submachine Gun, #19 Marco Automatic Rifle System "B" Model of 2016, Lupina Model 902 Pocket Double Rifle, Colt M1911A1/Legend Armory Model 65 Semi-Automatic Pistol (Helsturm), Perseus Arms P-236 Plasma Pistol (Project Operation Unthinkable), Evangelion Unit 01, Hrunting Greatsword, unnamed man-portable railgun weapon, Sans-44 Crux/Lomar-type Rocket Launcher, Evangelion Mask Helmet
Boombox (my friend drew it), #6 Ayanami-S Carbine, Armalite AR-18 Assault Rifle, Skull (also my friend), skeletonized Ayanami-S Carbine, front-view Ayanami-S, High-Class Skull, #6 Ayanami-S, #76 Skeletonized Ayanami-S Carbine (complete)
Ayanami Super Rifle - Second Revision, ASR 24-round box magazine, ASR 44- or 80-round drum magazine
Colt/Armalite M16 Assault Rifle, Chaos Canister Launcher Rifle, random bong
Unnamed Zarathustra rifle, incomplete revolver, #77 Ayanami Defensor Micro-S2-Cylinder Energy Beam Revolver[/spoiler]
EDIT - 4 September 2017:
Levels for Nukage (note lack of ceiling heights and sector light)
E1M1. Nothing too fancy here apart from a secret .600 DHC Lucky Joe revolver and a Full Auto weapon mod.
E1M2. You can find a Ripper mod (does exactly what it says) and a Firefly mod (from Destiny - headshots cause targets to explode), as well as the VSK7 Nightshade shotgun (from The Trooper) and the Sarukov DPMS-V Missile Launcher (from Project Operation Unthinkable). In addition, you might find the Trinity Coachcannon (POU), a Blink Drive (many, many sources - allows hyperfast instant movement, akin to teleportation), or that Gesicht Shadow, who drops a Thunic Eraser upon death (Thunic Set, equivalent to the SSG).
E1M3. Neat things here include the D80 Service Pistol (POU and R&D), the K-JACK (a homing photon torpedo launcher), the Templar (a beat-up, enchanted lever-action shotgun), the Gehiron AM10 Scimitar (R&D), and the exotic Sidewinder shotgun. Also of note - Flip Cock mod (for the Templar - it's 1991 pretending to be 1997 again!) and Nanocytes (haven't figured out what that does, or don't remember).
E1M4. Here you may find a Gesicht Frontliner (drops Thunic Subjugator) and some Minigunners (drops Gehiron Minigun), as well as the Lightning Saw and a Grenade Launcher weapon mod. Also of note here is the secret Pinky Demon (secret, out-of-universe enemy placements are a thing in Nukage - expect some familiar opponents in secret cubicles and such).[/spoiler]
Weapons for Nukage and Research & Destroy:
Upper left - Thunic Subjugator (automatic directed energy weapon) and Blaster (semi-auto energy pistol), Gesicht Frontliner, Egghead armor suit, Darkling Eviscerator (yay, nightmare creatures!). Bottom left - Insurgency Light Rifle (POU) and Sidewinder shotgun. Right side, top to bottom - Legend Armory Model 15, LAM15C, Legend Armory Model 17, Post-apocalyptic LAM17, unknown breech-loader pistol, Post-apocalyptic LAM15 and LAM15C, Salvo MR4 marksman rifle.
Francis MG9, Reptilian Commander A, Reptilian Grunt A, Reptilian Skirmisher A, Gesicht Vector Gunner, Infinite Vector (Thunic Set, heavy automatic directed energy weapon).
Close-up of Infinite Vector.[/spoiler]
New weapon concepts:
I'll post more as I sketch more things.