"Anyone See That?" and "Silent Knight" During the mission where you must track down the Penguin on his ship (it is one of the first main missions in the game), after your encounter with Tracey (Penguin's assistant) and her goons, you will reach the first predator room in the game. Remain crouched, sneak up to an isolated enemy, and perform a silent takedown. Do this to all six enemies in the room without being spotted to get the "Anyone See That?" and "Silent Knight"s. Note: If you have already passed this point in the game, there are tons of other opportunities to get these achievements/trophies, but you should definitely do this before completing the story. After completing a predator room, the enemies will not respawn.
"Flawless Display" Note: the starting point of Shiva's quest is not marked on the map. Go to the Gotham Merchants bank in "The Bowery" district and listen for a crying baby, then inspect the abandoned baby stroller in front of the Gotham bank to begin this quest. You will then have to complete a series of tasks for Shiva. It does not matter if her ninjas or other enemies hit you while doing the tasks. After doing all the tasks, meet up with her in Sheldon Park (marked on your map). Complete the fight with her without taking any damage to get the "Flawless Display". A good tactic to use to not get hit is to jump, hit an enemy once, and jump again. When jumping, the enemies will not have an opportunity to hit you. During the final phase of the fight, activate your Shock Gloves to defeat the enemies more quickly. If you get hit during the fight, pause the game, and choose the "Restart" option. The entire fight will start from the beginning, and you can try again. Note: It is possible to miss the Shiva fight in the story. If you miss the fight, you must start a new game and do Shiva's side quest to fight her.
"Free Flow Fifty" The first combat challenge, "Intensive Training", is perfect for doing the x50 combo. Enemies will not have armor or shields in this challenge. Reach Round 4 so there are enough enemies to build up a x50 combo. To ensure you do not get hit while fighting, perform a standard strike, then jump over an enemy, and repeat. None of the enemies will be able to hit you. It takes a little longer than countering and fighting the normal way, but it is effective. Do not perform any combo attacks or finishers -- so the enemies stay alive longer. If you have already unlocked the Shock Gloves, activate them to get a x2 multiplier with each hit.
"One Of Each" There are five different gadgets needed to get the "One Of Each", which are unlocked automatically while playing through the story. The following gadgets have to be used in one combo, without ever losing the combo multiplier:
"Point Counter-Point" When you fight Deathstroke eearly in the game, press Y or TRIANGLE to counter him each time he attacks. Attack Deathstroke with Batman's normal strike; doing so may initiate a QTE where you need to press the counter-button when it is displayed on the screen. If you press the button too early, or too late, your counter attack will fail, and you will get hit. If you get hit during the fight, pause the game, and select the "Restart" option. The entire fight will begin again, and you can try again. Note: It is possible to miss the Deathstroke fight in the story. If you miss the fight, you must start a new game and play until you reach the Deathstroke Boss fight to get the "Point Counter-Point".
"Point To Point" Use the Grapnel Gun and glide across the Gotham Pioneers Bridge (the large bridge connecting the south and north of Gotham City). You can do this at any point in the game while in Free Roam mode (even after completing the story). No upgrades are required. Go to one end of the bridge and keep shooting the Grapnel Gun at the wires to stay above ground. After shooting the Grapnel Gun, you must also activate the Accelerator by pressing A(2) or X(2) to avoid touching the wires. You may not land at any point while crossing the bridge. If you do, you must start over.
Do the following to earn 120,000 XP every 15 minutes and be able to purchase all upgrades at the start of the game. At Burnley, go to the indicated location on the rooftop and let the enemy kill you so you are saved at this location. When you spawn after dying, use the grappling hook to go back to the rooftop, silent takedown the first three enemies, then silent takedown the fourth enemy with a Knockout Smash to get a total of 8,000 XP. After getting the XP and the "Saving..." icon disappears at the bottom of the screen, pause the game and select "Restart" to start from the last checkpoint. Repeat this process as many times as desired.
Two-face In the G.C.P.D. Building, inside the S.W.A.T. Interrogation Room, one of the tables below a group of x-rays has a newspaper featuring the headline; "Harvey Dent Elected Gotham D.A.!"
Green Arrow Inside the arena room of the Final Offer there is a cargo container with "Queen Industries" on its side. "Queen Industries" belongs to Oliver Queen, a.k.a. the Green Arrow.
Rupert Thorne In the G.C.P.D. check out 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.The Late Waynes Just like in Arkham City, you can go back to the exact place where Bruce Wayne's were killed behind the theater in the Park Row/Bowery area.
Blaze Comics shop You can find a shop with the same name as the comics both Bruce Wayne and Clark Kent read as children.
The Phantasm On a workbench in the Batcave, next to his crime-board, there are two postcards from Andrea Beaumont. One is from Paris, the other from Rome. They both speak of searching for her father, referencing the DCAU film 'Mask of the Phantasm'.
Calendar Man On your last visit to Blackgate Prison, two-thirds of the way through before you open the double metal doors to reach The Joker and Bane, go right down a little side area you'll see an air vent. Travel through the vent and it'll drop you into a prison cell belonging to Calendar Man.
Jingle Bells, Batman Smells During your final Blackgate visit, Joker sings a bar of the “Jingle Bells, Batman Smells” song popularized by the Simpsons.
Green Lantern There's a billboard for Ferris Aircraft, where Hal Jordan was a pilot.
Zatanna and Ratcatcher Check out the back room of the My Alibi strip club to find Zatanna's hat and Ratcatcher's mask and gloves. There is also a poster for a magic act reading "Amazing Magic Show. The thrilling Zatanna."
Scarecrow At the start of the game in Blackgate Prison, you can view a visitors log. On it, Jonathan Crane's name appears signed into prisoner processing and hasn't signed out.
Other assassins In the Sionis Steel Mill, located in the loading bay depot, there are books on a desk that say "Cheshire," "David Cain" and "Black Spider" on them with red REJECTED stamps on them.
Arkham Asylum characters
Inside the G.C.P.D. building near the control room, one of the lockers is open and contains open case files, an ash tray full of cigarettes, and a picture frame of Aaron Cash and his family. Cash is a guard from Arkham Asylum who ultimately has his hand bitten off by Killer Croc.
You can find the apartment belonging to Dr. Penelope Young, who later appears in Batman: Arkham Asylum in Lacey Towers before working the Black Mask crime scene.
Gotham's mobsters The G.C.P.D. Building has pin-up boards and chalk boards with names such as Sal Maroni, Carmine Falcone, Carla Viti, Sofia Falcone, Lewis (Lew) Moxon, Rupert Thorne and Tony Zucco.
Catwoman In the G.C.P.D. building on one of the chalk boards is a family tree of the Falcone family, including the names "Selina ???".
Robin Like in Arkham City, posters of the Flying Graysons can be found in certain areas of the city. However, unlike City, these posters don't have the massive 'Cancelled' written across them. Instead, the posters reveal the act is 'Coming Soon.'
Clayface A poster for a film titled "Funny Faces" staring actor Basil Karlo, who famously later becomes transformed into Clayface.
DC heroes' cities Billboards inside the Final Offer advertise Metropolis, Central City and Coast City, the cities where Superman, The Flash and Green Lantern live.
Dr. Hugo Strange Dr. Hugo Strange's 'Strange Minds' building is still present in Park Row, just like in Arkham City. He is also referenced in Alberto Falcone's extortion tape.
Dancing Joker Stop punching Joker during the final encounter to watch him dance in place. You can walk around him and such but he’ll just keep dancing until you clobber him.
Reach Round 4 of the "Intensive Training" combat challenge and , abuse the trick of attacking enemies, then jumping over them to avoid their hits/counterattacks. Repeat this until you reach a x50 combo, without worrying about using combo attacks or finishers It gets even easier if you have unlocked the Shock Gloves, which provide a x2 multiplier on each successful hit when activated.