Pulled from a guide I found online, this is a list of the unlocks
{{Warning, may contain spoilers}} "Hard Times" Secret items. (Special thanks to BubbaKush for working out where the boots come from)
-The Relic: The collapsed mine, keep going foward till you hit then end, you will be wounded but gain the relic, go to the church in the top left to cure the wound.
-The Rifle: Go to the mexican and in the fight at the homestead dont let Cheech get killed.
-Snake Skin Boots: 2nd fight in Mexico town (Optional). Warning this is a very hard fight since you are vastly outnumbered.
"As Good As Dead" Secret items. (Special thanks to Lady Lyndis for working out the items)
-Shotgun Revolver: Rewarded for killing the 100 men the mystery man wants you to do.
-Skin Vest: The town of Hope/Graveyards. Go to Hope and search, after the old lady choose Abandoned Grave.
-Baby N9: Bank robbery optional mission. Save the Child Eater during the set up and survive with him.
"Graveyard Shift" Secret items. (Special thanks to BubbaKush and Bubba for finding out the items)
-Bonehand Rifle: Save the reverand fight, let the reverand join you after the fight.
-Ghost Town Fruit: Give items to the spirits 3 times. (Tabacco, Booze, Opium)
-Candle Of The Dead: Fight the demon prince, do not let the demon touch any of the alters.
"On Earth, as it is in Hell" Secret items. (Special thanks to Bubba for finding out the items)
-The Judge: Rescue H. Persons.
-Oxen Skull: Stolen from the Wizard after he dies.
-One-Armed Bandit: Evangelist Challenge (The Order is: Mark, Matt, John, and finally, Luke)
"In Gold We Trust" Secret items. (Special thanks to Bubba and Vaits for finding out the items)
-Serpent Amulet: Finish the excavation.
-Ivory Flintlock Pistol: Recruit Victor Suncove at the Old Outpost and he must survive until the last mission.
-Holy Musket: Dig up graves at the Old Cemetery
"Method In Madness" Secret items. (Special thanks to Mattimeo78 and Bubba for working out the items)
-The Revolving Revolver: Crafted through gunsmith tech.
-The Doomsday Clock: Max out engineering, have 8 parts and help the man repair the clock during an event.
-Meteor Bomb: Mine the meteor (Do not need to kill Turner).
"Law and Order" Secret items. (Special thanks to Bubba for working out the items)(Updated Mammoth Rifle, special thanks to Shindragan)
-The Judicator: Attack the Sanctuary after selectively killing the order members.
-Weird Monocle: At the Indian Tent, pay the Indian Outcast for information regarding the order member at the Indian Village. Take the pendant to the Indian Burial Grounds.
-Mammoth Rifle: Complete all the massacre missions and the devil will award it to you.
"A Matter of Time" Secret items. (Special thanks to Bubba for working out the items)(Updated Cañón Calavera, Special thanks to Motetta)
-Protector Ring Revolver: Return to the Lafórtuna Residence after dealing with his mercenary train.
-Tournament Trophy: Win the poker tournament. Prepare by buying the laxative from the Hospital and playing poker at the gambling den (intentionally losing to learn about the other players). At the event, eavesdrop on the arguing couple and slip laxative into an unattended drink to make it through the preliminary round. Follow the departing player into a back room and give him an extra dose of morphine so he fails to join the final table. Beat the good doctor by using your previous knowledge of his tells and use your ability to see the future to beat Jimmy.
-Cañón Calavera: Unlocked after killing Joaquim Perez (2nd area Cassandra scenario, you have to go to the area with the bonus supplies)
What does the special mining equipment do? (Stage 1)
-It seems to give you a chance to get more gold with certain equipment but it also can mess you up, a permenant disadvantage can be poisoned.
How do you get rid of the 'Cursed by the devil' disadvantage. (Stage 1)
It seems to be a permenant disadvantage.
Where do you find the 'Dex potion' for the location that requires it. (Stage 1)
During the quest to cure your father you have to go to the shady place and ask about cures, one of the places in the fortune teller who has the item for sale for about 15 gold.
Stage 2 items that unlock special things (Items need to be in your inventory not on a person or the game acts like you do not have said item)
3 Bottles of liquor to the indians will unlock new areas.
5 tobacco to the old man in the hills, followed by 1 liquor and 1 opium, he will then tell you about a secret treasure of gold in the bottom left worth 250 gold.
Poison Vial to poison the cannibals, you get it from the elixir merchant but have to drink it first meaning for the fight you will be at -2 hp, if possible use cards to counteract this effect.
Where is the saw for the tree? (Stage 2)
Its located at the sawmill which unlocks after you cause a certain amount of terror, you have to risk injury to get it, the reward for cutting down the tree is a bone amulet that gives +10 aim.
How do you get the ear trophy amulet? (Stage 2)
Chase down and kill the cannibals after winning to get the trophy.
Where do you find the "Rusty Peashooter"?
Un-equip all your weapons and enter combat to get it.