In the vanilla version of Doom, for example, when you shoot an imp, he always falls over and dies the same way. Brutal Doom introduces a variety of animations and "hit boxes," which detect which part of the imp’s body you shoot. This allows you to point a shotgun at an imp’s head and shoot it clean off, or shot him in the legs, watch him scream for help, then come close and kick him to death.
It may not sound like it, but there’s a very subtle, meticulous craft to SGtMarkIV’s imp mutilation. The animations are obvious additions, as are the new and improved weapons, but it’s the little things that make the biggest difference. The walking speed, the way blood now splatters and drips down from the ceiling, the extra bass added to shotgun blasts…"