For every step the role is above Fair, the victim loses a wound, starting at the least critical available wound level, and then to the next one. Bad shooting conditions will reduce the Shooting skill, rather than increase the needed result level. Armor makes bullets work like hand attacks, as in the Unknown Armies rules. If an AP round delivers a wound worse than a Flesh Wound, then don't check off the Flesh Wound box. Check off all the others as normal.
Guns kill people.
Most other rules from Unknown Armies , particularly madness, port over very well. Others will figure the extra skill arrangement is fine. I think that covers most of everything. They may be used with any gaming genre. While an individual work derived from Fudge may specify certain attributes and skills, many more are possible with Fudge.