This is discussion archived from a time before the current discussion method was installed.
Yoshi348: I have never, ever, ever had an enemy gib in Doom via shotgun, and I'm not even sure it's possible (beyond shooting explosive barrels, but at that point it's reasonable again). I suppose the chaingunner's "regular" death animation in Doom II could be construed as gibbing, though.
Nezumi: I believe there's a very small chance of it if you fire at a weak enemy absolutely point blank. Even then, it might take the double-barreled, and firing at point blank with both barrels of a double-barreled shotgun carrying buckshot, you would damn near gib someone, as I understand shotgun wounds. It'd actually be more along the lines of messily shredding them in half as the load of buckshot tore through their body, spreading inside them, but gibbing isn't a bad stand-in.
Phartman: Shotguns don't "gib" in Doom, because they use the same bullet-type damaging as the pistol and chaingun. Only explosives, plasma weapons and berserk power-ups will do that. You could probably make a patch that allows bullet weapons to gib, though.
By the way, buckshot won't spread that broadly at point-blank range. It doesn't leave the barrel as an expanding cone; assuming you use an unmodified choke, it leaves as a solid clump of shot that gradually "flares" out, so to speak. It'd make a gigantic hole in someone's torso at close range, but regular 00 or 000 buckshot cannot cut someone in half at any distance, even with two barrels at once (though it'd theoretically be possible with bolo shells, which consist of two lead balls joined by a length of steel cable).
Zeke: Due credit to my friend Dave, who introduced me to Army of Darkness, and made that perfectly-timed observation about blood.
The Gunheart: Do you think it's worth mentioning that ragdoll physics take this too far in the other direction some times? Nothing more disappointing than hitting a Combine soldier square in the face in Half-Life 2 only for them to be sent flying like Team Rocket.
