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