Batman: Return to Arkham - Arkham City

In order to unlock New Game Plus, you must finish the game on Normal or Hard.

Similar to Hard difficulty, attack indicators are removed. In addition you'll find many more armored thugs, and predator situations will include more jammers and thugs with mines. While side missions don't carry over, any progress on Riddler trophies do. While you start with all your weapons, you can't skip any of the primary missions, or open any TYGER MCP doors with Cryptographic Sequencer until the mission toward the very end of the game where you gain the MCP codes. A relatively fast run through the game in NG+ will take 3-4 hours, however that is excluding side missions that will take several more hours, which you need to complete to unlock the Perfect Knight - Day 2 achievement.

The only challenging boss is Mr Freeze. While in NG you only need to takedown Mr Freeze 5 times, in NG+ it is 10 times.

Using Detective Mode/Vision will cause a "meter" on the right side to increase. The meter will start turning red if you use it too long, and Mr. Freeze will eventually send out a jamming signal once that meter fills. Only use Detective Vision for short period to avoid this - you will find that you won't need it that much anyway given the high visibility in the room.

The order of how I did it was:
1 - Silent Takedown from behind
2 - Explosive Gel on a wall and detonate was he walks past
3 - Very shortly after, electrocute him in the standing water (batarang into the switch)
4 - Hide in the floor grate and complete a takedown
5 - Glide Kick (glide from one of the lab tables, not from the railings)
6 - Remote Electrical Charge on a generator
7 - Inverted Ledge Takedown (crouch on railing above a doorway and when he walks through press )
8 - Line Launcher to the back
9 - Disruptor on his gun
10 - Window Takedown (if you find that Mr Freeze's missiles break the windows, you can use the ceiling window and use the Sonic Batarang to lure him into place)