Critical Effects
One of the biggest complaints I had about D&D 4e is that a "critical hit" didn't really mean as much as they use to, and many people that discussed the topic missed the ways it was done in the past. In 4e a "critical" usually means not much more than "max damage", and "max damage" wasn't much different than being lucky on die rolls. I mean, a dagger would roll "max damage" 25% of the time as it is... That hardly seemed like anything special or dramatic.
I know that, as levels progress and magic weapons become more readily available, the damage and effects do add up. In one of the campaigns I'm running I'm playing a goliath tempest fighter that, when he crits, has a boatload of damage and effects piled on to the maximum damage. When he critical hits, he causes:
- Maximum damage on the main weapon (2d6 +17 = 29 damage)
- +4d6 damage on the main weapon, +4d8 if I have combat advantage (Chainreach Short Sword +4)
- +2d6 with Executioner's Bracers
- +1d10 with Devastating Critical feat
- Gains Resist 10 all until the end of his next turn
- If the critical hit is with the main hand, gets an attack with the off-hand as a free action.
So damage on an MBA rockets up from a mere 19-29 hit points of damage to a bone crushing 36-83 damage on a critical hit (plus an additional attack with the off-hand), almost three times as much. Then again, he was designed for this sort of thing; I don't imagine the "average" character being able to do that much.
That character is level 23, however; he's already working through his epic destiny. What about a character that's level one? Shouldn't rolling a natural 20 be something special regardless of your experience, above and beyond being lucky on the damage roll?
And there's another issue: what if the attack roll isn't a damaging roll? In one of the online campaigns I'm running we have an invoker that likes to use Whispers of Defeat every chance he gets. It gets an attack roll (Wisdom vs Will) but it doesn't actually cause any damage. Rolling a natural 20 on that means absolutely nothing, and I'm not even sure if the magic weapon damage bonus applies to that sort of attack.
So while looking around the 'net I found a "Critical Effect Chart" that seems to satisfy most of the issues. Here is the one I am currently using:
Critical Hit Effect: Roll a d20
1-2: Target deafened until end of target's next turn (-10 to Perception checks).
3-4: Target weakened until end of target's next turn (half damage against all targets).
5-6: Target blinded until end of target's next turn (everything has concealment, -5 to basic attacks).
7-8: Target slowed until end of target's next turn (movement speed reduced to 2).
9-10: Target pushed 1 square and knocked prone; attacker can shift 1 square as immediate reaction.
11-12: Attacker makes another melee or ranged basic attack against target as a free action.
13-14: Attacker gains 3 temporary hit points for each tier (+3 THP in Heroic tier, +6 THP in Paragon tier, +9 THP in Epic tier).
15-16: Target dazed until end of target's next turn (only one action, move, minor or standard).
17-18: Target is bleeding (ongoing 5 damage, save ends).
19: Target is stunned until end of target's next turn (no actions).
20: Attacker adds extra 1w (2w for Paragon tier, 3w for Epic tier) to the damage total.
I apply the above to ANY "attack roll", so a natural 20 on Whispers of Defeat still has the possibility of causing some more lasting effects. Also note that this is meant to be in addition to the documented rules: weapons still do maximum damage and magic weapons and implements still do additional damage due to their enchantment.
In the above chart, if the creature rolls another 20 and the source of the attack doesn't have an explicit "W" defined, use the attack's base die, multiplying x2 for Paragon tier and x3 for Epic tier. For example, a warlock's Eldritch Blast would cause an additional 1d10 per tier.
The blog also contains a "Critical Miss" chart. I considered it at first, but after discussing it with my players I elected not to use it. Reason? I think it's too much. We're talking about seasoned adventurers here, and I just don't feel that they're going to go all Keystone Kops 5% of the times they make an attack roll (the odds are even higher for burst effects). When a monster critically misses, it's DM's choice whether to turn it in to a bumbling idiot - I have had undead trip over themselves and bandits fire arrows in to the backs of their allies because of a critical miss - but I don't think the players should ever be that stupid.
All in all, it works out real well. Players get excited when they have to roll for the critical effect, even during the first encounter of a level 1 campaign.