In 5th Edition D&D, a maximum roll on a d20 only counts as a “critical” when attacking. But, rolling a 20 feels really good! So it stinks when you roll a 20 and you don’t get some extra mechanical benefit.
Many folks have mulled the merits (and drawbacks) of installing such a system in other parts of the game. Most often, this is discussed in the context of skill checks. That discussion kind of loses the forest for the trees; since you shouldn’t be calling for a skill check that a player can’t pass, a 20 should always be a success.
Now, I don’t have a problem with a little bit of narrative flavor, but it’s tough to drive the narrative home if you don’t have some mechanical bite. All that 20 earned you was a few extra fancy words.
What if there were some rolls that players had to make that could use a little extra mechanical bite to make that 20 not feel “wasted”? Well, there’s one type of roll. And critical successes have already snuck in!
I’m talking about saving throws! Players need to make them. They don’t get any benefit when they roll a 20 vs. rolling a 19.
Death Saving Throws
Sneakily, this mechanic kinda already exists in the game. When you roll a death saving throw, and you roll a 20, you automatically regain 1 HP, taking you out of the death saving throws mechanics. You can participate in the battle again! That’s a huge mechanical benefit!
If we can apply benefits like this to normal saving throws, then we can install some of that excitement back into rolling a 20! Here’s my homebrew suggestions for benefits you can give a player rolls a 20 on a saving throw:
On the opposite side of the coin, we have fumbles (rolling a 1). While I’m generally not a fan of mechanical teeth to fumbles (as they are more punishing to competent characters), saving throw fumbles don’t suffer from some of the same multiattack quandaries as attack fumbles.
So, if you want to add save fumbles to your game, what I suggest doing is adding criticals back! Wait, what? Well, when you picked a spell with a saving throw instead of a spell attack, you lost your chance to score a critical hit and roll twice the damage die. You can just add double damage (dice) against creatures that roll a critical fumble on a save.
Note that this will juice up the power of AoE damage spells, which trigger saving throws, versus targeted attack spells, that can already benefit from a critical hit. It’s very possible this was taken into account when benchmarking AoE and targeted spell damage. So, there are balance concerns with save fumbles.
While you can certainly apply these rules equally to PCs and monsters, I would suggest only giving these benefits to players.
Critical saves are a little fiddly, so they’ll just increase DM workload for monster management. On the player side, they’re already sitting there doing nothing, so they’ll be happy to hold on to their little nugget until their turn rolls around. 20s don’t feel as good for DMs as they feel “oof” so we’re not really losing out on the good feels we’re trying to capture for the player.
Save fumbles can be dangerous to PCs, as a big spell damage roll can easily result in a dead PC. Also consider the impact to AoE spells above. While I’d be wary implementing save fumbles in the first place, I would be doubly cautious applying them against PCs.
If you want some more saving throw hacks, check out Death Saves Revived or Meat Grinder Mode. Support us on the ThinkDM Patreon, where you can get additional content, early releases, and personalized help on your own design. If you have any suggestions for different critical save benefits, please let us know in the comments below.