Player characters gain a 20% bonus on the critical hit table (a +20 bonus is applied to the Critical Hit table roll), moving it up one table entry, ensuring more damage. This perk does not affect the chance to cause a critical hit.
Taking this perk is the only way to get a critical hit roll over 100, which yields instant death in half of the hit areas.
The instant kill effect is independent of damage. It's even possible to kill something without any damage.
Synergizes well with Sniper and high Luck, as these convert each shot to critical.
Scripts triggered by a critter's death do not fire upon "instant-death zero-damage criticals," such as pariah dog. These can be prevented by also having the Living Anatomy perk which makes zero-damage attacks impossible.