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