Here is the full list of all 40 Colt Canyon achievements.
Revive a companion or player.
Defeat the first boss.
Kill all enemies in a level.
Survive an ambush.
Unlock a locked crate.
Rescue 10 prisoners.
Kill more than one enemy with a single projectile.
Find yourself a companion.
Rescue one prisoner.
Defeat the second boss.
Defeat the final boss. Go get your partner!
Rescue your partner and complete the game.
Rescue 100 prisoners.
Defeat the bear using nothing but melee attacks.
Kill more than 5 enemies with one dynamite.
Die from fire.
Die from poison.
Die from explosion.
Die from a trap.
Die from getting kicked by a horse.
Have 5 or more companions follow you at once.
Kill 1.000 enemies in total.
Reach your partner without being spotted by any enemies outside of boss fights or ambushes.
Kill more than 500 enemies in a single run.
Get hunted by wolves.
Kill the first boss with just pistol-ammo weapon and no upgrades.
Reach the second area without having taken any damage.
Kill all enemies in a level using only throwable weapons.
Let the bear step on a bear trap.
Defeat the slaver without hurting any slave.
Kill the final boss without the use of explosives.
Start a Loop Run.
Rescue your partner with all 4 base characters.
Take out 15 enemies in a row with melee stealth kills without being spotted.
Rescue your partner without having any upgrades applied.
Defeat the bear without using any dodge rolls.
Rescue your partner without ever using a melee attack.
Reach the bandit boss in under 20 minutes.
Have 7 additional hearts.
Finish a Loop Run.