It keeps DOOM Retro’s software-rendered look, but adds support for VOXELDEF and KVX files from the VoxelDoom PK3. We also fixed several issues with voxel height, clipping, colors, close-range crashes and visible gaps between voxel pixels.
You need to supply your own DOOM IWAD and download VoxelDoom_v2.4.pk3 separately. Neither is included. This is focused Voxel Doom support, not general GZDoom PK3 compatibility.

Download: [https://tuintje.org/tuinprojects/?project=doomretro]
Credit to Brad Harding for DOOM Retro and Cheello (Daniel Peterson) for the voxel artwork. I handled the idea, direction and a lot of testing.