This achievement can be rushed in the very beginning of the game by starting the new scenario using customized option Full Deck. But after the tutorial you wouldn't have any character that has all five cards slots opened, so it would be also necessary to complete the first tactical mission after tutorial. Then Father would have all five card slots available in the character screen and all you need it to select five cards from the same column for him and add joker card. Achievement would pop-up once you accept the card selection.
Easy "Arizona Colts" Achievement
If you unequip the weapons to a character, he/she will start the tactical encounters with the Rusty Peashooter - a very bad handgun. To get this achievement, complete a tactical encounter firing ONLY with the Rusty Peashooter - you can have a character with other weapons in hand, but it's important that you NEVER shoot with these weapons. It's easy to get, specially if you play on easy - some damage enhancers (with cards combination, or equipment) are however really recommended to boost the damage of these rusty handguns.
Easy "Blind Justice" Achievement
Practically you can get this achievement naturally while playing the game, but if you wish to rush for it, it can be done playing the first mission of the first scenario (Hard Times), just decline the tutorial and play on your own trying to shoot as many enemies through the tents as you can (after mission is failed or complete, just restart the scenario again). I believe you can also get the achievement by completing the tutorial 10 times, as it assumes one "blind shot" during education.
Easy "Fastest Gun in the West" Achievement
This one is easy and can be achieved in the very first tactical mission of the first scenario (Hard Times), if you disable the tutorial and shoot the thug with the first action without moving. If the shot fails, restart the mission.
Easy "High Stakes" Achievement
When you are controlling the Dr. Gorman, you will encounter a location named "Maple Falls", where you can find an unbeatable dice player who will bet his head (literally X-D) to a game. Buy the "Loaded Dice" at the store and play with them (there is a specific option on "Maple Falls") and you will get his head... and this achievement.
Easy "Human Resources" Achievement
Each killed enemies on a combat encounter will give you five Ether - so you need to kill fifteen enemies to get this achievement. In the mission where Dr. Gorman and Phineas must defend the laboratory from the cultists the enemies are endless, so use this mission to get this achievement.
Easy "Sudden Death" Achievement
"Equalization" is the card ability of the Ten of Diamonds: cost sixty luck, reduce EVERY character's HP to 1 - yours and enemies. To get this achievement, you must use this ability on the first combat turn of any mission and finish it. It's easier than it sounds, because even if you cannot use items to restore your character's HP, you can use abilities. The hand bonus "Straight" (the sequence of cards 9-10-J-Q-K or 10-J-Q-K-A, the jokers can replace any card of the sequence), give you HP regeneration, so after using Equalization, you can simply wait under cover to regenerate and then go to slaughter all you enemies.
Another useful ability is "Shadow Salve", the ability of the Jack of Diamonds, that give you health regeneration when you're not in direct sunlight - inside a building, or in the shadows, it's like the "Straight" hand bonus, but using only a single card. Personally speaking, I got this achievement in the last mission of the first campaign (using the tunnel), with a character with the Straight bonus and another with the Shadow Salve. At the beginning of this mission you are inside your house, without any enemies on sight (they will arrive soon however, so move any character away from the door), so you can use Equalization without any problem, and then wait that your characters with regeneration fill they health bars.
Easy "What Goes Around, Comes Around" Achievement
To get this achievement, you must first unlock the ability to purchase the Canon Calavera. Simply defeat Joaquim Perez and do the extra tasks in the second mission of A Matter of Time and you will be able to buy his gun from the Fate Trader. Play a second run through of the campaign, purchase the Canon Calavera and defeat him again while using the gun as the killing blow.
Various Steam Achievements
Complete the indicated task to unlock the achievement.
Achievement
How to unlock
A Gift Scorned
Complete "A Matter of Time".
Aces in the Hole
Assemble the Five of a Kind hand.
Arizona Colts
Complete any tactical encounter without firing weapons other than the Rusty Peashooter.
Blind Justice
Kill 10 enemies with blind shots (no line of sight).
Brimstone Killer
Kill a demon while your character is in demon form.
Daring but Careful
Complete "In Gold We Trust" having lost no more than 150 peons.
Double Excellence
Fully develop two technological domains during "Method in Madness".
Drowned in Blood
Complete "Law & Order".
Everlasting Fame and Fortune
Complete "In Gold We Trust".
Fastest Gun in the West
Kill an enemy in the very first action in a tactical encounter.
Fight No More Forever
Complete any tactical mission without firing a shot.
His Leniency, The Inquisitor
Complete "Law & Order" having committed at most 2 massacres.
On Earth, as It Is in Hell
Establish Warren's new world order.
Once Upon a Time in the Weird West
Complete all Scenarios.
Raw Deal
Complete "Hard Times".
Requiem for a Gunfighter
Restore the order in the Weird West.
Sanity Engineered
Complete "Method in Madness".
Sudden Death
Use Equalization in the first combat turn, then complete the mission without raising your characters' Hit Points with items.
The Aspirton Incident
Complete the Aspirton Bank Robbery in "As Good as Dead" before demons arrive.
The Meaning of Life
Complete "Graveyard Shift".
The Searcher
Unlock all Trinkets in the game.
The Shootist
Complete any tactical encounter firing sure shots (100% Chance to Hit) exclusively.
The Wild Bunch
Use 30 different playable characters in at least one tactical encounter.
Through Thick and Thick
Complete "Graveyard Shift" without anyone being hungry at any time.
Treasures of the Sierra Madre
Use 25 different usable items at least once.
Trickshooter
Kill an enemy with a bullet ricocheting off at least 3 different objects.
Vengeance Served Cold
Complete "As Good as Dead".
Welcome to Even Harder Times
Complete every Scenario on Hard, every Scenario with Injuries and every Scenario with Ironman enabled.
Welcome to Hard Times
Complete a single Scenario on Hard difficulty, with both Ironman and Injuries enabled.