Batman: Arkham City

- You can't get every Riddler trophy you come across right away, you might have to come back with a new gadget. The pink ones are only for Catwoman.

- Riddler's hidden question marks are back. If you see one, find some place to see the whole thing and tap the Detective Mode button.

- When the game is over, you'll get to go back and get anything you missed.

- There are easter eggs everywhere and some of them have achievements for finding them.

- The only immediately useful upgrade you can get is the one that slightly slows time when your freeflow combo hits x12, everything else you can get when you feel it's necessary.

- When your first set of Augmented Reality glide challenges becomes available, do them for a very useful grappling hook upgrade.

- The "Catch" achievement involves a character who you can find on top of the ferris wheel by the steel mill after a certain point in the game. Throw a remote batarang at him. This is also the start of a side-mission.

- There's no time limit on finding new leads for side-missions.