Here is the full list of all 38 Hard West 2 achievements.
Collected every card in the game.
Killed 60 Hellspawns.
Maxed out loyalty with Laughing Deer.
Maxed out loyalty with Old Man Bill.
Maxed out loyalty with Lazarus.
Killed 666 enemies.
Finished the game on the Easy difficulty.
Finished the game on the Hard difficulty.
Finished the game on the Nightmare+ difficulty.
Completed all world map side objectives in Chapter 3.
Finished the game on the Normal difficulty.
Finished the game on the Nightmare difficulty.
Finish "One Last Ride" in no more than 12 rounds with all objectives completed.
Visited every location in all Chapters.
Form sets of Royal Flush with 4 posse at the same time.
Form sets of Straight with 4 posse at the same time.
Form sets of Full House with 4 posse at the same time.
Finish "The Great Train Heist" in no more than 10 turns with all objectives completed.
Killed 80 Revenants.
Maxed out loyalty with Flynn.
Maxed out loyalty with Clalish.
Finish "Wanted: Lady Shrike" in no more than 15 turns with all objectives completed.
Completed a mission using only Melee weapons.
Finish "A Plague Upon This Land" in no more than 12 rounds with all objectives completed.
Completed a mission using only Handguns.
Finish "Riftwalkers" in no more than 10 turns with all objectives completed.
Completed a mission using only Rifles.
Finish "3:10 To Heaven" in no more than 1 round with all objectives completed.
Completed a mission using only Shotguns.
Killed 50 Shadow Dancers.
Completed all world map side objectives in Chapter 1.
Finish "Frostbitten in Calla Calla" in no more than 10 turns with all objectives completed.
Finish "O'Kane Farm" in no more than 8 turns with all objectives completed.
Killed 100 Bandits.
Finish "Flynn's Vision" in no more than 10 turns with all objectives completed.
Finish "Blasting Out" in no more than 8 turns with all objectives completed.
Finish "Fooling The Hangman" in no more than 4 turns with all objectives completed.
Finish "Daredevils" in no more than 8 turns with all objectives completed.