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