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