Here is the full list of all 26 Call of Juarez: Gunslinger achievements. It takes around 15-20 hours to unlock all of the achievements on Windows.
Complete the Story on True West difficulty.
Unlock all skills in Story Mode.
Forgive your lifetime nemesis.
Collect all Nuggets of Truth.
Complete the Story on hard difficulty.
Complete the Story on any difficulty.
Kill your lifetime nemesis honorably in a duel.
Find and kill Jim Reed.
Discover a shipwreck in the Missouri swamps.
Shoot a flying stick of dynamite and the one who threw it on a single Concentration.
Kill a bird during a winning duel.
Win a duel honorably in under 0.6s.
Complete the duel challenge, winning all duels honorably.
Complete all Arcade missions.
Get all Arcade Mode stars.
Kill a shotgunner with a close-range shotgun blast.
Fight in Concentration for 15 minutes.
Score the maximum of 3 stars in any Arcade mission.
Reach combo level of 20.
Kill 5 enemies when falling down through the air.
Unlock both exclusive weapons in a single category of skills in Story Mode.
Shoot through a hole to kill an enemy that hides behind a shield.
Find all Nuggets of Truth in a single mission.
Find and kill Johnny Ringo.
Give it to them straight about your meeting with Pat Garrett.
Unlock a skill.