http://forum.zdoom.org/viewtopic.php?...
Recent builds of GZDoom have more robust support for shader mods, here's some footage of one, by torridgristle, called RetroShader that emulates low resolution + Playstation 1 style jiggling vertices. Also set is "palette" style tone mapping which emulates the 8-bit color look of ZDoom's software renderer.
To be clear, source video is 1080p with OpenGL rendering, it's just emulating those old artifacts for aesthetic effect :]