Batman: Arkham City

					
Achievements:
50x Combo (Bronze)

Objective: Complete a combo of 50 moves (any play mode, any character)
Acid Bath (Bronze)

Objective: Save the damsel, but is she in distress?
Aggravated Assault (Bronze)

Objective: Stop all assaults in Arkham City
Bargaining Chip (Bronze)

Objective: Reunite the separated couple
Bronze Revenge (Bronze)

Objective: Obtain 24 medals on the original Arkham City ranked maps (as Batman)
Campaign Bronze (Bronze)

Objective: Obtain 36 medals on the original Arkham City campaigns (as Batman)
Campaign Silver (Bronze)

Objective: Obtain 72 medals on the original Arkham City campaigns (as Batman)
Catch (Bronze)

Objective: Find someone to play remote Batarang catch with
Chimney Sweep (Bronze)

Objective: There is only one way in
Communication Breakdown (Bronze)

Objective: Clear the airwaves
Conundrum (Bronze)

Objective: Rescue the first hostage from Riddler
Distress Flare (Bronze)

Objective: Answer the call for help
Flawless Freeflow Fighter 2.0 (Bronze)

Objective: Complete one combat challenge without taking damage (any character)
Forensic Expert (Bronze)

Objective: Collect enough evidence to locate the gun for hire
Freefall (Bronze)

Objective: Don't look down
Fully Loaded (Bronze)

Objective: Collect all of Batman's gadgets and upgrades
Gadget Attack (Bronze)

Objective: Use 5 different Quickfire gadgets in one fight (any play mode)
Gladiator (Bronze)

Objective: Last man standing
Gotham Base Jumper (Bronze)

Objective: Jump off the tallest building in Arkham City and glide for 1 minute without touching the ground.
I'm Batman (Bronze)

Objective: Become the Bat
Intellectual (Bronze)

Objective: Rescue the fourth hostage from Riddler
IQ Test (Bronze)

Objective: Solve the first riddle
Lost And Found (Bronze)

Objective: Uncover the secret of Arkham City
Mastermind (Bronze)

Objective: Rescue the second hostage from Riddler
Mystery Stalker (Bronze)

Objective: Reveal the mystery watcher
One-Armed Bandit (Bronze)

Objective: Hammer the point home
Pay Your Respects (Bronze)

Objective: A moment of remembrance
Perfect Freeflow 2.0 (Bronze)

Objective: Perform a perfect combo including all of Batman's combat moves (any play mode)
Puzzler (Bronze)

Objective: Rescue the third hostage from Riddler
Ring Ring (Bronze)

Objective: Answer a ringing phone
Savior (Bronze)

Objective: Save the medical volunteers
Silver Revenge (Bronze)

Objective: Obtain 48 medals on the original Arkham City ranked maps (as Batman)
Stop the Clock (Bronze)

Objective: Time is running out
Storyteller (Bronze)

Objective: Have 12 murderous dates with Calendar Man
AR Knight (Silver)

Objective: Complete all augmented reality training exercises
Brainteaser (Silver)

Objective: Rescue the fifth hostage from Riddler
Broken Toys (Silver)

Objective: Destroy it all
Campaign Gold (Silver)

Objective: Obtain all 108 medals on the original Arkham City campaigns (as Batman)
Contract Terminated (Silver)

Objective: Stop the contract operative
Dial Z For Murder (Silver)

Objective: Stop the phone booth killer
Exit Stage Right (Silver)

Objective: All the world is a stage
Genius (Silver)

Objective: Rescue all the hostages from Riddler
Ghost Train (Silver)

Objective: Fight for survival
Gold Revenge (Silver)

Objective: Obtain all 72 medals on the original Arkham City ranked maps (as Batman)
Hide And Seek (Silver)

Objective: A deadly game of hide and seek
Sandstorm (Silver)

Objective: We are legion
Serial Killer (Silver)

Objective: Track down the serial killer
Twice Nightly (Silver)

Objective: Complete New Game Plus
Wrecking Ball (Silver)

Objective: Stop the unstoppable
Perfect Knight – Day 2 (Gold)

Objective: Complete every challenge in Arkham City – Main Story, Side Missions, Upgrades, Collectables, New Game Plus and Riddlers Revenge (as Batman)
Platinum (Platinum)

Objective: Congratulations!
DLC: Catwoman DLC
Campaign Kitty (Bronze)

Objective: Obtain all 108 medals on the original Arkham City campaigns (as Catwoman)
Feline Revenge (Bronze)

Objective: Obtain all 72 medals on the original Arkham City ranked maps (as Catwoman)
Sphinx' Riddle (Bronze)

Objective: Complete all 40 of the Catwoman Riddler grid items
Arkham City Sirens (Silver)

Objective: Drop in on an old friend
Family Jewels (Silver)

Objective: Retrieve your stolen goods
Pick Pocket (Silver)

Objective: Steal the score of a lifetime
DLC: Robin DLC
Campaign Wonder (Bronze)

Objective: Obtain 114 medals on the original Arkham City and Robin Bundle Pack campaigns (as Robin)
Robin Revenge (Bronze)

Objective: Obtain 78 medals on the original Arkham City and Robin Bundle Pack ranked maps (as Robin)
DLC: Nightwing DLC
Campaign Nightwing (Bronze)

Objective: Obtain 114 medals on the original Arkham City and Nightwing Bundle Pack campaigns (as Nightwing)
Nightwing Revenge (Bronze)

Objective: Obtain 78 medals on the original Arkham City and Nightwing Bundle Pack ranked maps (as Nightwing)
Game Cheats:
Unlockable Costumes

There are various secret costumes or skins that are available for Arkham City through preordering or the Collector's Edition:
1970s Batman:
Preorder at EB Games (AU)

Preorder at ShopTo (UK)

Preorder at Toys 'R' Us (US)
Animated Series:
Preorder at JB HiFi (AU)

Preorder at MightyApe (NZ)
Batman Beyond:
Preorder at Game (AU)

Preorder at GameStop (UK)

Preorder at MightyApe (NZ)
Earth One:
Preorder at JB HiFi (AU)

Preorder at MightyApe (NZ)
Red Robin:
Preorder at Game or Gamestation (UK)

Preorder at Best Buy (US)
Sinestro Corps Skin (PS3):
Included with Green Lantern on Blu-ray (Best Buy)
The Dark Knight Returns:
Included in the Collector's Edition
Alternate Ending:

To unlock the alternative ending for Arkham City, you need to have access to the Catwoman DLC. With this done, on Catwoman's third mission, head right when you are given the choice of right or left.
This will set up the alternate ending – remember that you can revert following this so it doesn't change the rest of the main game.
Hidden Message:

Search for the coordinates X700, Y490 on the Cryptographic Sequencer to intercept a radio frequency that contains the following repeating numbers: 9, 23, 9, 12, 12, 18, 5, 20, 21, 18, 14, 2, 1, 20, 13, 1, 14. The message is decoded as 'I WILL RETURN BATMAN'.
Unlock New Game Plus Mode:

When the game has been completed under the Normal or Hard difficulty setting you will be able to retain any previously earned Experience points and gadgets. In New Game Plus mode there will not be any counter icons on thugs and they will have different configurations and be tough to defeat from the start of the game. The Bosses will also be tougher.