Grab the latest version of GZDoom here: https://zdoom.org/downloads
How to use mods:
1. Extract GZDoom to a new folder (name it whatever you want) and drop your doom2.wad in there.
2. Run GZDoom.exe at least once and then close it. You will see a newly generated .ini file inside your GZDoom folder.
3. Scroll down to [Global.Autoload], below this, type "Path=$PROGDIR/modname.modfiletype" without quotations.
4. Once finished save your changes to the .ini file and run GZDoom.
SmoothDoom.pk3 (8.36Mb) - Smooth Doom. Adds more frames to various assets to make their animations appear less jerky - Gifty
Source: https://forum.zdoom.org/viewtopic.php?t=45550
SmoothTextures.pk3 (571.81k) - Adds more frames to liquid surfaces to make their animations appear less jerky (must be loaded after Smooth Doom) - Gifty
Source: https://forum.zdoom.org/viewtopic.php?t=45550
SmoothDoomFaithfulCasings.pk3 (156.63k) - Replaces Smooth Doom's high quality bullet case impact sounds with more authentic lower quality ones from Shadow Warrior (must be loaded after Smooth Doom) - Gifty, ddave
Source 1 : https://forum.zdoom.org/viewtopic.php?t=45550
Source 2: https://ddavegames.neocities.org/
SmoothDoomFaithfulLiquidSFX (80.9k) - Replaces Smooth Doom's high quality water impact sounds with more authentic ones from Heretic (must be loaded after Smooth Doom) - Gifty, ddave
Source 1 : https://forum.zdoom.org/viewtopic.php?t=45550
Source 2: https://ddavegames.neocities.org/
SmoothDoomSilentCasings.pk3 (4.44k) - Makes Smooth Doom's bullet case impact sounds silent (must be loaded after Smooth Doom) - Gifty, ddave
Source 1 : https://forum.zdoom.org/viewtopic.php?t=45550
Source 2: https://ddavegames.neocities.org/
D64CROSSHAIRS.PK3 (2.02k) - Doom 64 crosshair, 3 variants included - ddave
Source: https://ddavegames.neocities.org/
PSXLight.wad (3.19k) - Gives certain walls a preset color value to make the game appear more like the PSX version - Quantum Dranger
Source: https://www.doomworld.com/forum/topic/98004-generalized-psx-lighting/
Sbrightmaps.zip (1,118k) - Adds glowing textures to to walls and monster eyes - Z86
Source: https://forum.zdoom.org/viewtopic.php?t=29792
PSSFX-PINKYFIX.wad (1.83Mb) - Modified version of PlayStation sound effects WAD. Pinky demon now uses original pain and hunting sounds from PC version - ULTRA_LASER, ddave
Source 1: https://www.doomworld.com/forum/topic/71713-playstation-sound-effects-wad/
Source 2: https://ddavegames.neocities.org/
PLAYERLAND.WAD (3.46k) - Replaces the player's landing "oof" sound with the footstep landing sound from Heretic (if using with PSSFX mod, it must be loaded after) - ddave
Source: https://ddavegames.neocities.org/
HQPSXMUS.WAD.zip (330.44Mb) - High Quality rips of the PSX music - dksd
Source 1: https://www.moddb.com/games/doom-ii/addons/psx-soundtrack-replacement-high-quality
NOGODMONO.pk3 (0.297k) - Stops god mode from turning the screen monochrome - ddave
Source: https://ddavegames.neocities.org/