Doom 2 [DeathMatch]

There seems to be something strange with
the IDDT cheat (the “map-mode”).  It works
on the Nightmare level, whereas the others
don’t.
But the real interesting thing is :
Hold [Alt] while typing IDDT 3 times, on
the map screen in deathmatch mode enables
you to see all monsters and your human
enemies!
This may not work on all versions (surely
not on version 1.9 and above) but we tought
it was too important not to mention.