I Am the Night Mode:
This mode will become available when you have beaten New Game Plus without dying once which means you must complete every mission and quest of the main campaign without making a single fatal error.
Unlock New Game Plus:
When you have completed the main campain in Normal mode or above New Game Plus will become unlocked. In this mode you will retain ALL your unlocked items and the challenges will be harder.
Big head mode
Hold L1 + R2 and rotate the Right Analog-stick clockwise ten times at the cryptographic sequencer . Repeat the code to disable its effect.
Complete the indicated task to unlock the corresponding costume.
1989-2006 Classic Tim Drake Robin: Purchase the "Infinite Earths Pack".
Adam West: Included in the PlayStation3 exclusive "Knightfall Pack".
Arkham Origins Deathstroke: Gamestop, Best Buy, Target, Walmart, or Amazon pre-order bonus or purchase the "Deathstroke Challenge Pack".
Batman 1 Million: Download the free DLC, then register with WBID.
Batman Blackest Night: Earn Prestige in Multiplayer mode.
Batman Dark Knight: Complete all Dark Knight Challenges.
Batman Earth 2: Included in the the "Batman Legends Pack" pre-order bonus.
Batman Injustice: Earn all medals in Challenge mode.
Batman New 52 Graphic: Capture all Most Wanted targets in Story mode.
Batman Noel: Find all Enigma Datapacks.
Batman ThrillKiller: Included in the the "Batman Legends Pack" pre-order bonus or purchase the "Infinite Earths Pack".
Batman: Dark Knight of the Round Table: Included in the the "Batman Legends Pack" pre-order bonus.
Blackest Night 2006-2008 Tim Drake Robin: Purchase the "New Millennium Pack".
Brightest Day Batman: Purchase the "Batman Arkham Origins – Season Pass".
Earth-2 Bruce Wayne: Purchase the "Infinite Earths Pack".
Earth-2 Dark Knight: Link your WBID to the Batman: Arkham Origins mobile game.
Earth-2 New: Purchase the "Infinite Earths Pack".
First Appearance 1939: Purchase the "New Millennium Pack".
Futuristic Batman: Included in the PlayStation3 exclusive "Knightfall Pack".
Gotham by Gaslight Batman: Purchase the "Batman Arkham Origins – Season Pass".
Initiation Bruce Wayne skin: Purchase the "Initiation" DLC.
Injustice Deathstroke: Pre-order bonus or purchase the "Deathstroke Challenge Pack".
Judas Contract Deathstroke: Pre-order bonus or purchase the "Deathstroke Challenge Pack".
Knight of the Round Table: Purchase the "Infinite Earths Pack".
Long Halloween: Included in the the "Batman Legends Pack" pre-order bonus.
New 52: Complete all Most Wanted missions or purchase the "New Millennium Pack".
Noel: Find all Enigma Datapacks or purchase the "New Millennium Pack".
Red Son: Unlock ten costumes in the Batman: Arkham Origins mobile game or purchase the "New Millennium Pack".
The Long Halloween: Purchase the "Infinite Earths Pack".
Worst Knightmare: Earn all achievements/accomplishments/trophies and get a 100% game completion.
Green Arrow reference
In the interior of the Final Offer, in the same area as the "fight arena", there is a cargo container with "Queen Industries" on its side. "Queen Industries" belongs to Oliver Queen, a.k.a. the Green Arrow.
Harvey Dent reference
While in the G.C.P.D., up in the evidence locker you can see a newspaper clipping of Harvey Dent's win in the election for Gotham City D.A.
Rupert Thorne reference
In the G.C.P.D., look carefully at the bulletin boards in the squadron rooms. On the walls are newspaper clippings and mugshots with police reports. One of these reports references Rupert Thorne; another one of Gotham's infamous crime lords.
Complete the following tasks to unlock PlayStation trophy rewards.
Platinum (Platinum): Congratulations!
Shut Down (Bronze): Shut down an entire Tower Network.
Counter-intelligence (Bronze): Decipher one Extortion File.
Enigma Unravelled (Bronze): Collect all Enigma items.
First Riddler Trophy (Silver): Collect every collectible.
One down, several to go (Bronze): Complete a Most Wanted entry.
The Innocent and the Predatory (Silver): Capture all of Black Mask's Assassins.
Shadow Vigilante (Bronze): Master the Shadow Vigilante Dark Knight track.
Gotham Protector (Bronze): Master the Gotham Protector Dark Knight track.
Worst Nightmare (Bronze): Master the Worst Nightmare Dark Knight track.
World's Greatest Detective (Bronze): Master the World's Greatest Detective Dark Knight track.
Legend of the Dark Knight (Silver): Complete all Dark Knight challenges.
Crime Scene Investigator (Bronze): Complete all Casefiles.
Crime Fighter (Bronze): Stop 20 Crime in Progress.
Thanks, old friend (Bronze): Hear everything Alfred has to say.
Personal Trainer (Bronze): Obtain all the medals on Combat Training maps.
Perfectionist (Silver): Obtain all the medals on Custom maps in Challenge mode.
I've Got This (Bronze): Acquire all upgrades.
Free Flow Fifty (Bronze): Reach x50 Combo.
Anyone see that? (Bronze): Complete a predator encounter without ever being spotted.
What hit me? (Bronze): Take down 100 enemies who didn't know you were there.
Silent Knight (Bronze): Complete a predator encounter using only silent takedowns.
Point to Point (Bronze): Glide across Bridge without touching ground.
Around the World (Bronze): Use the Batwing to travel to all Fast Travel points.
Flawless Display (Bronze): Successfully battle Shiva without taking any damage.
Point Counter-Point (Bronze): Complete Deathstroke without failing a single counter.
One of Each (Bronze): Use every Freeflow Focus gadget in one combo.
Air Marathon (Bronze): Glide 26 miles total.
Medalist (Silver): Obtain all medals on the original Ranked Maps in Challenge mode (as Batman).
Olympian (Silver): Obtain all medals on the original Campaign maps in Challenge mode (as Batman).
Voice of the People (Bronze): Scan 20 Anarky Tags.
Clean Streets (Silver): Complete all Most Wanted missions.
Give Them Something to Believe (Silver): Complete New Game Plus.
I Am The Night (Gold): Finish I Am The Night Mode.
Predator Paragon (Bronze): Take down 6 different Elites in a match, using 6 different methods as Batman or Robin in multiplayer.
Killing Joke (Bronze): Reach max level with the Joker faction in multiplayer.
Fallen Knight (Bronze): Reach max level with the Bane faction in multiplayer.
Gotham All-Star (Bronze): Reach max overall level in multiplayer.
Clutch (Bronze): Kill a Hero to bring back your entire gang when at 0 reinforcements on a full multiplayer server.
Tales of Gotham (Bronze): Win a round of each map with each faction in multiplayer.
I Like Those Odds (Bronze): As a Hero, defeat 4 Elites within 40 seconds without using melee in multiplayer.
Not An Ordinary Criminal (Bronze): As an Elite, earn 4000 XP in a single multiplayer match.
Arsenal, Awesome (Bronze): Fully upgrade a weapon in multiplayer.
Legend (Bronze): Earn a level of prestige in multiplayer.
Know Thy Enemy (Bronze): Defeat each of the enemy players at least once in a multiplayer match.
Additionally there are six secret trophies.
City of Assassins (Bronze): Identify Black Mask's assassins.
One eye open (Bronze): Defeat Deathstroke.
Nobody that matters (Bronze): Who is the Joker?
Everyone wears masks (Bronze): Find the Black Mask.
One Rule (Silver): Save a life.
Perhaps sooner, Perhaps later (Gold): Defeat the Joker.