Here is the full list of all 36 Desperados III achievements.
Complete 5 of the Baron's Challenges.
Kill all 3 golden chickens.
Interrupt an important healing procedure.
Execute a plan with all five characters.
Jump from a tower into a cart of hay.
Enjoy some cupcakes during a picnic.
Kill 31 hidden Mimimi devs.
Kill 200 guards using Cooper's double shot.
In the first part of the mission, burn 5 guards at once with oil traps.
Mind control 25 guards with Isabelle.
Kill DeVitt.
Kill 6 guards at once using only a single skill.
Earn 90 badges.
Find a patient for the dentist.
Return the money to the bank.
Decide the outcome of a duel.
Knock out your father.
Defeat Frank.
Take care of DeVitt.
Kill 10 small animals in one mission.
Kill 75 Long Coats.
Hide 750 bodies.
Snipe 50 guards with McCoy.
Kill 1,000 guards.
Meet Frank on a boat.
Make guards follow Kate for 1,000 meters total.
Kill 75 guards with Bianca.
Kill 15 of the hidden Mimimi devs.
Find Wayne.
Kill 500 guards.
Kill 50 guards using the environment.
Hide 250 bodies.
Make someone follow your footprints for 25 meters.
Blow up a bridge.
Kill 5 guards at once with dynamite.
Finish a mission on "Desperado" difficulty.