If you are about to die, just pause the game and hit the restart button, or if are already dead, hit the power button(sensor)immediately because if you don't do it in time, it wont work. Or if you hesitate but does not show the enemy, you may lose ALL your progress on the game. To avoid losing your progress, copy your profile on another storage device(like a flash drive or hard drive)
This feature is the same as the one in Arkham City Batman. To enable Big Head mode take out the cryptographic sequencer and hold L1 and R2 and rotate the right analog stick clockwise until Batman's head becomes big.
Check out the following video if you are struggling to find where Enigma has placed jamming devices at each of the seven GCR Comms Towers. When you get inside the GCR Comms Towers and removed the interface you must destroy the 10 Network Relays in the area when they are revealed on the map.
The following video will help you find the Enigma Datapacks/Extortion Files that are hidden in Gotham City which Enigma is threatening to release. Extortion Files 1 and 2 (comprising of 20 Datapacks) are hidden throughout Park Row. To enter the Courthouse, you must complete Anarky's side mission. To enter the Church, you must complete Black Mask's side mission.
The following video will show you how you can get 120,000 XP in 15 minutes so you are able to buy ALL the upgrades at the beginning of the game. Go to the indicated loation in Burnley to begin (map below).
Batman Legends Pack: Pre-order bonus (Walmart in US, JB Hi-Fi in Australia). This pack includes the Earth 2 Batman, Batman ThrillKiller, Dark Knight Of The Round Table, and The Long Halloween costumes.
Brightest Day: Included with Season Pass purchase.
Deathstroke: Pre-order bonus (Amazon, Best Buy, GameStop, Target, Walmart), or available for purchase.
Gotham By Gaslight: Included with Season Pass purchase.
Infinite Earths Pack: Available for purchase. This pack includes the Batman ThrillKiller, Classic Tim Drake Robin (1989-2006), Dark Knight Of The Round Table, Earth-2 Bruce Wayne, Earth-2 New, and The Long Halloween costumes.
Knightfall Pack: PS3 Exclusive pre-order bonus. This pack includes the Adam West and futuristic Batman costumes.
New 52 Metallic: DC Comics exclusive bonus.
New Millenium Pack: Available for purchase. This pack includes the Blackest Night 2006-2008 Tim Drake Robin, First Appearance 1939, New 52, Noel, and Red Son costumes.