Tuesday, January 7, 2020

Graded success for roll-under d20

This is a sort of half-baked add-on inspired by Call of Cthulhu 7e's graded difficulty system for roll-under d100 resolution. It assumes 3d6-based ability generation a la BX, and uses the same modifier scale, albeit towards a different end.

Basically, any ability score rated 3-18 has a "crit" range from 1 to (4 + ability modifier):*

Ability Score 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
Crit threshold 1 2 3 4 5 6 7

You could also implement a simple skill system:

UNSKILLED:
   Miss: Goes badly
   Success: Works, at a cost.
   Crit: Works
COMPETENT:
   Miss: Doesn't work - can push at risk
   Success: Works
   Crit: Works well
SKILLED:
   Miss: Works at a cost
   Success: Works
   Crit: Works well

So what to do with all this? I dunno there's plenty of good games out there, play one of those instead. You're welcome.

2 comments:

  1. This is a cool idea, thanks! Very much appreciated by some one who is obsessed with d20 roll under attribute checks.

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  2. Good stuff. It makes stats more important, but also has more "success at a cost" to make them less important?

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