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