I keep thinking about a new challenge menu based around the American Weapons - but uses other in game items in order to compete them. A sequence of events if you will. For example:
“Snowball” Shoot a tick out of the air with the N9 on Himfjall, while wearing Ski Boots.
“1 in the Chamber” Finish off any FOA Level 4 Rival using the last remaining bullet in any of the American Weapons wearing the full Exosuit.
“L.O.T.B” Destroy 10 machines with one clip of the N60 at night, while wearing an eye patch.
“Fear the Reaper” Destroy the Reaper at 3 Windmills - using only US Weapons, while wearing Spiral Glasses.
Destroy an Apocalypse Harvester with only the N16, while a boombox or radio is active while in the Farmlands.
Any other suggestions guys…let’s get creative.