Continually updated.
These are the credits for sprites/textures/sounds. All programming done by me, with CanyonJack making most of the original maps.
id/Bethesda - Zombieman, Shotgunguy, Demon, Lost Soul, Pain Elemental, Cacodemon, Mancubus, Arachnotron, Imp, world textures, classic Doom weapons, effects, beta rifle, Barrel, Daisy, item pickuos
Seargant Mark IV, RedAr, Quaker540, MrYayYayIfy, JMartinez2098, GOLDEN MOBSTEЯ72: Assault Rifle
Ghastly_dragon, Eriance (Marisa Kitsune), Xim, scalliano: Auto Shotgunguy
Simploo, Bethesda - Eternal-style PG [edited to replace hands, changed muzzle effect]
Fistful of Frags Team, SomeOtherDoomGuy, jdredalert - Mare’s Leg
Bethesda, me: HUD/menu Elements
Seargant Mark IV: M14 Rifle, DUST effects, pistol, Helicopter, Kicking, blood effects, executions/fatalities
Seargant Mark IV, Tomtefars, Azona: SSG
Mike12, id/Bethesda [sounds]: Chainsaw
SoniK.O.Fan, DoomNukem: Shotgun
Skulltag Team, Zap: Announcer
xenoxols: Gunslinger revolver
DoomNukem: Revolver
Captain Toenail/Raven: Sentry Gun
CanyonJack, Neccronixis, Simploo, Me, Bethesda - Praetor weapon edits
Franco Tieppo, id/Bethesda: Upgrade bot, glorykill drop icons
Darch - Preacher revolver
RooM-specific credits:
n64q - Even Simpler, Cacopog sprite
CanyonJack - Exoplanet, Crash Site
SneakSniper - Hangar