Here is the full list of all 29 Rustler achievements.
The base game contains 28 achievements, and there is 1 DLC pack containing 1 achievements.
Complete 100% of the game, including all quests, side activities, and obtaining every other achievement.
Complete 100% of the game without dying nor getting caught even once.
Wield all weapons available in the game at least once.
Kill 500 people.
Complete the main story line.
Complete all quests for Salazar.
Catch all horses for This Neigh Land.
Collect 20000 gold pieces.
Herd a total of 50 NPCs to mass during the church herding side activity.
Use Pimp-A-Horse 20 times.
Gain and then remove a maximum Wanted rating without dying and with no quest active.
Collect all horseshoes.
Survive for 5 minutes at maximum Wanted rating.
Collect 20 bodies during the body collecting side activity.
Complete all quests for the Herbalist and the Doctor.
Complete all quests for the Spanish Inquisition.
Complete all quests for the Knights of the Holy Grail.
Complete all quests for the Priest.
Complete all quests for the Loan Shark.
Collect 5000 gold pieces.
Come first in 10 races.
Win 10 fights in the MMA side activity.
Block 10 attacks in 60 seconds.
Plow the fields 10 times.
Kill an NPC with a cow.
Kill 5 NPC in 5 seconds.
Set the amount of blood particles in settings to x5.
Complete the first quest.
Successfully complete the Halloween event.