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