I've always liked these things ... so here are the rules i use in BXDH:
FUMBLE (You rolled a natural 1 to hit)
1-3: you are disarmed/weapon is temporarily unable to be used
4-5: enemy gets a free attack against you
6: your gear is damaged [it gets save, failure is broken, success is damaged until repaired]. If using a ranged weapon 50% you need to make an immediate ammo usage check instead.
CRITIAL (you rolled a natural 20 to hit)You hit and roll double damage dice
- not double the total damage, just double the dice
- for example, if you do 1d8+2, on a critical you do 2d8+2
1-3: double damage dice
4-5: act again, right now (attack, disengage, chug a potion, whatever)
6: combat maneuvers - you disarm the enemy, break their armor, push them somewhere or get to move yourself. Likely narrated by the GM with Player input? I don't want this to overshadow some of the character's special abilities.