Hello everyone. This mod is a texture "tweak" which changes every classic Doom level into early version of any Doom Builder level. So that means, that brightness of every sector is 192, walls mostly have a "STARTAN" (or "STARTAN2") texture, floors have a "floor0_1" texture, ceiling have a "ceil1_1" texture.
You can see the results of this experiment here:
This mod supports all Doom IWAD files; requires GZDoom 1.9 or above, latest Zandronum and latest ZDoom sourceports to run.