The attached map runs a script which (I think) sets up a camera texture to use the view from a baron of hell and then prints the camera texture to the screen (presumably using a hudmessage) so that your view becomes that of the baron. However, when this happens, decals become a bit transparent in the camera view and the edge of sprites do not seem to get shown properly either.
Procedure:
Load the file then cheat to get the weapons.
Use something like the rocker launcher that makes big decals (easier to see) and splatter a few decals around the room taking care not to kill the baron (it won't attack you).
Hit the switch and watch.
I think what happens is that certain areas of the decals make the hudmessage more transparent so that you can see the player's view through it. For example, in this screenshot, you can clearly see the red and silver of the switch that is in front of the player through the decals on the pillar.
Perhaps less obvious is the slight "aura" around the player sprite in this screenshot.
Like I said, it may just be that the WAD is abusing the system but, on the other hand, it could be indicating that there is something not quite right elsewhere.
