Oniria

Oniria is a single-level PWAD for Doom II, authored by Aluqah and designed for ZDoom. The new color scheme (PLAYPAL and COLORMAP), which plays a significant role in the level, was created by Jon Dowland. In Oniria, you are having a nightmare from which you cannot awaken. You find yourself in a bizarre world where everything is black-and-white with the exception of the color red. The only thing you can do is to explore the world with the hope that the nightmare would eventually come to an end.

Oniria screenshots