I've got a little piece of my .INI file here, after I did a little bit of tweaking to make the monsters sound how they sounded in the actual games. No longer do Shotgunners sound like demons. And no longer do Lost Souls sound like they're gibbing with every move.
SOUND_PISTOL = "wav/dspistol.wav";
SOUND_SHOTGUN = "wav/dsshotgn.wav";
SOUND_PLASMA = "wav/dsplasma.wav";
SOUND_ROCKET = "wav/dsrlaunc.wav";
SOUND_BARREL = "wav/dsbarexp.wav";
SOUND_RELOAD = "wav/dswpnup.wav";
SOUND_DOOROPEN = "wav/dsbdopn.wav";
SOUND_DOORCLOSE = "wav/dsbdcls.wav";
SOUND_ITEM = "wav/dsitemup.wav";
SOUND_AMMO = "wav/dssgcock.wav";
SOUND_BFG = "wav/dsbfg.wav";
SOUND_PUNCH = "wav/dspunch.wav";
SOUND_CLAW = "wav/dsclaw.wav";
SOUND_FBALLFIRE = "wav/dsfirsht.wav";
SOUND_FBALLHIT = "wav/dsfirxpl.wav";
SOUND_BRLMOVE = "wav/dsstnmov.wav";
SOUND_POWERUP = "wav/dsgetpow.wav";
SOUND_PUSHFAIL = "wav/dsnoway.wav";
SOUND_PLDEATH = "wav/dspldeth.wav";
SOUND_SKULL = "wav/dssklatk.wav";
SOUND_ROCKETEXP = "wav/dsrxplod.wav";
SOUND_TELEPORT = "wav/dstelept.wav";
SOUND_DIEIMP = "wav/dsbgdth1.wav";
SOUND_DIESER = "wav/dspodth1.wav";
SOUND_DIEFORMER = "wav/dspodth3.wav";
SOUND_DIEDEMON = "wav/dssgtdth.wav";
SOUND_DIECACO = "wav/dscacdth.wav";
SOUND_DIESKULL = "wav/dsskldth.wav";
SOUND_DIEBARON = "wav/dsbrsdth.wav";
SOUND_DIECYBER = "wav/dscybdth.wav";
SOUND_DIEARACH = "wav/dsspisit.wav";
SOUND_ACTIMP = "wav/dsbgact.wav";
SOUND_ACTFORMER = "wav/dsposact.wav";
SOUND_ACTSER = "wav/dsposact.wav";
SOUND_ACTDEMON = "wav/dsdmact.wav";
SOUND_ACTCACO = "wav/dscacsit.wav";
SOUND_ACTSKULL = "wav/dssklatk.wav";
SOUND_ACTBARON = "wav/dsbrssit.wav";
SOUND_ACTCYBER = "wav/dscybsit.wav";
SOUND_ACTARACH = "wav/dsspidth.wav";
SOUND_HITIMP = "wav/dspopain.wav";
SOUND_HITSER = "wav/dspopain.wav";
SOUND_HITFORMER = "wav/dspopain.wav";
SOUND_HITDEMON = "wav/dsdmpain.wav";
SOUND_HITCACO = "wav/dsdmpain.wav";
SOUND_HITSKULL = "wav/dssklatk.wav";
SOUND_HITBARON = "wav/dsbrssit.wav";
SOUND_HITCYBER = "wav/dsdmpain.wav";
SOUND_HITARACH = "wav/dsspidth.wav";
SOUND_PAIN = "wav/dsplpain.wav";
SOUND_LEVER = "wav/dsswtchn.wav";
SOUND_CHAIN1 = "wav/dssawhit.wav";
SOUND_CHAIN2 = "wav/dssawful.wav";
SOUND_HOOF = "wav/dshoof.wav";
SOUND_DIEPAIN = "wav/dspedth.wav";
SOUND_ACTPAIN = "wav/dspesit.wav";
SOUND_HITPAIN = "wav/dspepain.wav";
SOUND_ACTVILE = "wav/dsvilact.wav";
SOUND_HITVILE = "wav/dsvipain.wav";
SOUND_DIEVILE = "wav/dsvildth.wav";
SOUND_ATKVILE = "wav/dsvilatk.wav";
EDIT: I made a few more changes since things didn't sound quite right, and now everything's as close to as it should be. Kornel, take a look again.
Edit Deux: We do not have Arachnotron sounds, I repeat, we don't have Arachnotron sounds. That's why they sound like the Spider Mastermind. I will find them, download, and send to Kornel.