Press Up(2), Down(2), Left, Right, Left, Right, [Esc], [Enter] at the main menu. Note: Enabling this code will unlock the "Should Auld Acquaintance..." achievement, and will not prevent other achievements from being unlocked.
Developer reference
Enter the cemetery where Lady Comstock's mausoleum is located. Search the gravestones to the left of the entrance to her grave. One of the graves is features the handwritten word "SNIGHT", which is a reference to Mike Snight, a member of the development team.
Easy gear
Start "Return to the Hall of Heroes" and use the doors behind you to enter The Hall of Heroes. Once inside, exiting to the Plaza will cause items in the Soldier's Field area to respawn. You can use this to your advantage to farm gear. Go to the Plaza and defeat the Vox and Founders. You should also use the sky-lines to travel to the lower Gondola Station and defeat the Founders and Fireman. There is also a Motorized Patriot in its entrance hall. Simply stun it, go to the elevator, and use it to return to the Soldier's Field boardwalk. Find the toy store next to the carousel and lift its shutter to enter. Use Shock Jockey on the generator near the locked door to open it, allowing you to collect a piece of random gear. Return to the Hall of Heroes by using the elevator and the sky-lines. Enter the doors to the museum. Once inside collect the Salts and repeat the process.
Easy lockpicks
On the way out of Hall of Heroes after fighting Slate, ride two sky-lines to find get into fight that includes a firefighter that always has a lockpick. Defeat him, collect the lockpick, and return to the Hall of Heroes. After entering the building again, exit and ride the sky-lines to find the same firefighter. Repeat the process as many times as desired.
Easy Silver Eagles
Go to the Hall of Heroes and possess the vending machine on the right side of the steps that lead to the building's entrance to get a random amount of money. Enter the Hall of Heroes, run down the hall, and refill your Salts. Leave the building, return to the vending machine, and repeat the process.
Various Steam Achievements
Complete the indicated task to unlock the achievement.
Achievement
How to unlock
A Real Pistol
Killed 25 enemies with the Broadsider Pistol.
Aerial Assassin
Killed 20 enemies with a Sky-Line Strike.
Armed Revolt
Assisted the gunsmith.
Auld Lang Syne
Completed the game in 1999 Mode.
Big Game Hunter
Killed 100 enemies with the Founder Huntsman Carbine or Vox Burstgun.
Blood in the Streets
Completed Emporia.
Bolt From the Blue
Killed 5 enemies with a headshot while riding a Sky-Line.
Bon Voyage
Killed 20 enemies by knocking them off Columbia.
Coins in the Cushion
Looted 200 containers.
Combination Shock
Performed all 8 of the Vigor combinations.
David & Goliath
Killed 20 "Heavy Hitter" enemies.
Dress for Success
Equipped a piece of Gear in all four slots.
Eavesdropper
Collected every Voxophone.
First Class Ticket
Boarded The First Lady.
Grand Largesse
Spent $10,000 at the vending machines of Columbia.
Hazard Pay
Killed 10 enemies by utilizing environmental hazards.
Heartbreaker
Killed a Handyman by only shooting his heart.
Here Little Piggy
Killed 30 enemies with the Founder Pig Volley Gun or Vox Hail Fire.
Higher Learning
Completed Comstock House.
Industrial Accident
Killed 20 enemies with a Sky-Hook Execution.
Infused with Greatness
Collected every Infusion upgrade in a single game.
Kitted Out
Fully upgraded one weapon and one Vigor.
Loose Cannon
Killed 25 enemies with the Paddywhacker Hand Cannon.
Lost Weekend
Killed 5 enemies while you are drunk.
Master of Pyrotechnics
Killed 20 enemies with the Barnstormer RPG.
Mind Over Matter
Killed 20 enemies using Possessed machines.
More for Your Money
Lured 3 enemies into a single Vigor trap 5 times.
On a Clear Day...
Killed 30 enemies with the Bird's Eye Sniper Rifle.
On the Fly
Killed 30 enemies while riding a Sky-Line.
Passionately Reciprocated
Killed 150 enemies with the Founder Triple R Machine Gun or Vox Repeater.
Raising the Bar
Upgraded one attribute (Health, Shield, or Salts) to its maximum level.
Saw the Elephant
Completed the game on Normal difficulty or above.
Scavenger Hunt
Complete the game in 1999 Mode without purchasing anything from a Dollar Bill vending machine.
Seasoned to Taste
Killed 30 enemies with the Peppermill Crank Gun.
Shock Tactics
Retrieved Shock Jockey.
Should Auld Acquaintance...
Unlocked 1999 Mode.
Sightseer
Used all telescopes and Kinetoscopes in the game.
Skeet Shoot
Killed 5 enemies while they are falling.
Stone Cold Pinkerton
Completed the game on Hard difficulty or above.
Strange Bedfellows
Killed 20 enemies using allies brought in through a Tear.
Street Sweeper
Killed 50 enemies with the Founder China Broom Shotgun or Vox Heater.
Tear 'em a New One
Opened 30 Tears.
The Bird or The Cage
Completed The Hand of the Prophet.
The Roguish Type
Used Elizabeth to pick 30 locks.
Tin Soldier
Completed the game on Easy difficulty or above.
Vigorous Opposition
Killed 75 enemies either with a Vigor or while the enemy is under the effects of a Vigor.
Welcome to Monument Island
Reached Monument Island.
Well Rounded
Used all 8 Vigors against enemies.
Working Class Hero
Completed Factory.
Written in the Clouds
Completed Lighthouse.
Vigor combos
Use the indicated Vigors in the listed order on the same enemy to perform corresponding combo.
Possession + Shock Jockey
Possessed Lightning Conduit that electrocutes enemies.
Possession + Devil's Kiss
Possessed Fire Conduit that burns enemies
Devil's Kiss + Charge
Multiple spreading fire bombs spawns at target.
Murder of Crows + Devil's Kiss
Sets crows on fire and burns enemies.
Murder of Crows + Shock Jockey
Electrifies crows and electrocutes enemies.
Bucking Bronco + Devil's Kiss
Launches a cluster of bombs from a floating target.
Search the indicated location to find the corresponding Vigor.
Possession
Go to the Fair's exit and get it from one of the stores to the left of the ticket vendor leading into Raffle Park.
Devil's Kiss
Looted from a defeated fireman heavy-hitter after the Raffle encounter.
Murder of Crows
Defeat the hooded enemies in the chapel inside the Fraternal Order of the Raven building. It is located on the altar near the large George
Washington mural.
Bucking Bronco: Go through the ticket station before reaching the pavilion leading to the gondola en route to the Hall of Heroes. The Vigor is located just as you leave the larger ticket chamber.
Shock Jockey
Found on Slate in the Hall of Heroes.
Charge
Located inside a small office behind a locked gate on the way to the Shantytown. The gate will be open on your way back to the Plaza of Zeal after leaving the Police Impound.
Undertow
Check behind the desk in the Office of Jeremiah Fink before leaving through the exit.
Return to Sender
After leaving the Port you will find a locked door that leads to the Salty Oyster Bar. You must activate a secret button that becomes selectable after you open the lock into Founder's Books and listen to the Voxophone recording about the button. Once the button is pressed, you can find the The Vigor on a table inside the Salty Oyster Bar.