Underground Radio:
During the Kundang Camp level, you will eventually end up chasing Sadono 
underground. Your CO will advise you that they will no longer be able to 
communicate with you while you are underground, due to interference from 
copper. 
However, if you get caught by a guard or an alarm is sounded, your CO will be 
able come over your earpiece saying that you need to watch the alarms. The 
female counterpart will also say something, even though they are not supposed to 
be able to reach you.

Level Select:
When you complete the game under the normal or hard difficulty setting, when 
you go back into the game make sure you go over towards the level select instead 
of checkpoints. You could lose your data and have to do it over again if the wrong 
choice is made.

Easier Aiming With Sc-20k:
Press R3 to zoom in the sniper scope, then press L1 to hold your breath. You 
should be able to get a good shot while Sam remains still.

Various References:
On the first half of the Jerusalem level, there is a book store directly behind an 
alley with a swinging lamp. Next to it is another smaller alley with a swinging lamp. 
If you look inside the large window you can see many different picture references 
to The Punisher, Ubi Soft's XIII, an anime, and a picture of the infamous 'Sniper 
Kitty' among many other things. Use the binoculars to get a much better look. 

Prince Of Persia References:
On the mission when you are on the train, look in the second car where the guard 
is located. Knock him out then go behind the fenced door. Look down you will see 
a magazine featuring Prince Of Persia.

Find Mines Easily:
In order to find mines in the camp mission, turn on the thermal vision.

Multiplayer: Talking To Teammate After Losing:
When you are playing in an online match and lose all of your respawn lives, mute 
your teammate and then unmute him. Both of you can now communicate with 
each other.

Easier Aiming With Pistol:
To aim better with the pistol, press Square to pull it out. The crosshair should 
appear normal. Then, press Up on the D-pad and the crosshair should become a 
laser sight. This makes it very easy to aim, since the laser sight is smaller and 
thinner than the normal crosshair. This allows fast kills and head shots. If you are 
in dark corners and have the laser sight on, the enemies will notice and attack you.

Defeating Norman Soth:
After you have climbed up the elevator cables and have gotten on top of the other 
elevator, crawl through the hole in the wall. Norman Soth and two other 
mercenaries are on the top pathways. While in the hole, there will be one guard on 
the top path, slightly to the right. You should be able to shoot him in the head. 
Then, a timer will start and you will have one minute to kill Norman Soth and his 
other mercenary. When you shoot the first mercenary, drop out of the hole onto 
the first pathway. The second mercenary will go to exactly where the you shot the 
first mercenary. Shoot the second mercenary in the head. The second guard will 
be aiming at the hole, so he will not see you if you drop out of the hole. The last 
person to kill is Normon Soth. Start running down the pathway and turn left on the 
second to last walkway on the left. Look up and turn on your thermal vision. You 
will see Normon Soth. Get a clear shot and shoot him in the head. After that you 
must retrieve the smallpox box from the top pathway. If you are on the second to 
last pathway on the left, go up the ladder. There will be another ladder; use it to 
climb up. Drop off the ledge onto the pathway. Run down the middle pathway to 
find the smallpox box. 

Knocking Out Guards:
To knock out a guard without using a Sticky Shocker or a Air Foil, shoot a Sticky 
Cam at their head. It must hit him directly in the head for the guard to get 
knocked out. 

Television Free: Drowning Your Victims :
In Television Free (mission 8), you will have a chance to go down into the sewer. 
When you knock out a guard, drag their unconscious body into the water then click 
into thermal view. You can watch the life slowly slip out of their bodies.

Stealth:
To move quieter, crouch down and walk slower. This will make your steps softer, 
and keep you undetected to a limit. 

Shoot Without Fear:
When you are at a point that you can only use non-lethal attacks, make sure that 
you have the SC-20K and at least one Sticky Cam. Instead of waiting to sneak up 
on a person, shoot them in the head with the Sticky-Cam. This knocks them out 
without using 'lethal methods'. Aiming high is the key to knocking the person out 
because the Sticky Cams have a short range. After the attack you can pick your 
cam up and use it again.