Cheat mode:
Press L1(2), R1(2), Square(2), Triangle(2), Circle(2) at the main menu. There is 
no confirmation message. Start a game then pause and enter the options screen. 
The "Cheats" option will be unlocked at the options menu. 

Extreme mode:
Successfully complete the game under the hard difficulty setting to unlock the 
extreme difficulty setting. 

Healing falling teammates:
If one of your teammates falls to the ground, throw a smoke grenade near him. 
Then, get your health packet out and heal him.

Destroying armored vehicle or tanks: 
Use Jones to run up to the vehicle or tank. Lay an anti-tank mine next to it, in turn 
sacrificing jones Temporarily to take out the vehicle or tank. 

Use Jones to run close to the tank, then plant a C4. Throw a smoke grenade on 
the tank, run for the nearest cover, then blow it up. 

Have one of your team members run by the tank to distract it. Then, run up to the 
tank, plant C4, and blow it up (risking your life). You can heal him with the other 
team member. 

Tanks are weak in the following locations: their rear; in front, in between the 
armor over the tracks; and where the gun barrel meets the turret.