Dark Fort is a pen-and-paper roguelike that is the precursor to Mork Borg.

The goal for this challenge is to create some sort of "new" mechanic for the Dark Fort system, no matter how small (or big). This can be a game mechanic, something new such as radiant storytelling, etc. Unique settings for the dungeon crawl are also welcome as well, but let's keep the theme decidedly G R I M. 

To get a good idea of what Dark Fort is about, check out this fantastic article by Liber Ludorum. 

UPDATE: Here's another killer two-part feature that goes into detail about the mechanisms of Dark Fort via Skeleton Code Machine.

Here are some fantastic examples (free and otherwise) to use as inspiration. Play a couple and then get to designing!