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