A critical hit caused by enemy on any hit, depending on RNG roll, can deal extra damage, up to instant kill, complete with bloody death animation, different death jingle (I am suggesting 1st 8 notes of Beethoven`s 5th symphony) and harsher death penalty, all optional. Another consequence of critical hit is inducing status effects, including permanent delibrating ones, such as permajinxes in vanilla ZC.
Can it be fun?