I see the Dungeon Crawler Carl backerkit ended this morning with $13.3M USD raised. I just learned about it around noon today so I didn't back, but I did just watch the video connected to the campaign describing the mechanics and I have some thoughts.
First & foremost it's very straightforward. D20+skill of 1-20 vs target number, all dice player facing, degrees of success from fumble (roll of 1), fail, near miss, success, big & biggest success.
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