Criticals are a gameplay mechanic in Dark Souls.
General Information
Criticals are performed in what is considered the most vulnerable areas of enemies. There are three types of criticals: backstabs, ripostes, headshots and plunging attacks.
Critical attacks do bonus damage based on a weapon's critical stat. Most weapons possess a critical multiplier of 100, but Thrusting Swords and Daggers have a higher critical multiplier, and thus do more damage when executing a critical attack. Thrusting Swords also have a hidden multiplier that increases the damage of ripostes further, making them more suited to these attacks than Daggers.
Ripostes will do more bonus damage than backstabs, but can also be considered harder to execute, as they need a parry or a guard-break to happen.
The plunging attack is the rarest and most damaging critical. For this strike a higher ground is required, in which the player must jump and while falling hit de normal attack button, thus making the plunge attack dependant on the terrain.
The Hornet Ring increases the damage of critical attacks by an additional 30%. Wearing the ring also changes the animation of backstabs and ripostes when using certain weapons against human enemies. Headshots are not affected by the Hornet Ring.