Find the following outfits in the corresponding locations:
Look for Vinny Mortarello in the Fulton Street Station. There is an open window in an apartment building across from Shrote's building. Go through the window to get the Construction Outfit and Collectible #45.
Look for Jimmy the Grape in the Canal Street Station. Talk to him to activate the objective. Pete's in an apartment building down Grinder's Lane. There is a parking lot outside. Pete's inside room 261. Break in and kill the enemies. Get the Fireman Outfit.
The Jungle outfit is located in Hunters Point Alley inside the same room as Collectible #97.
Find Dana Cutrone in Canal Street Station and talk to her. You have to get her keys back from her boyfriend. Once in the apartment grab the Lumberjack Outfit and collectibles #4, 40 and 90.
Potato Sack outfit
In Chinatown, look for a flashing object near the Darkling portal. Shatter the glass and grab the Potato Sack Outfit that is sitting against the alley wall near metro exit.
The Roadworker outfit is located in the City Hall Station inside the train.
When you are in "Otherworld" (you will go there once you die the first and second time), the Germans soldiers usually get back up after you kill them. The only way to make sure they remain dead is to devour their hearts.
To keep the zombies dead when you die, kill them with the demon arm and throw them off the ledge. Note: This only works outside since if you throw them off the ledge inside a building, they won't die and simply follow you up to the level you are on. You can also devour their hearts to keep them dead.
About three hours into the game, after the cold storage part, you will end up in a hallway with a bunch of doors you can open. The middle door will have some computers and an enemy that didn't hear the gunfight because he is watching a television with headphones on. Kill him to access the television and be able to change the channel. Change the channel and some music videos and cartoons will play. Wait a few seconds to see what is coming on next. There will be one channel with some cheesy music and words, as well as a white lines coming out. This movie is actually the 1955 film The Man With The Golden Arm starring Frank Sinatra. The entire movie will play on this television.
-When you are in Jenny's apartment, sit down with her and the entire film To Kill a Mockingbird will play.
To defeat the Darkness in the castle (after the gate has been blown open), go up to every chair you see in the main room. Each chair will prompt you to activate it. Note: This gives away your Darkness powers for the time being. After the Darkness appears as a red/evil Jackie, remove any guns so that just your hands are out. This will stop his attacks. Then, walk up to him without any guns out and a prompt should appear to "Accept Him". The fight will then be over.