Teammate picks lock
Use the following trick to make your teammate following you pick a lock. Quickly press [Up], [Right], [Down] and quickly move away. This does not always work the first time -- you may have to try again. If done correctly, you will see the teammate that is following you rubbing his hand on the door, and you wil lhear a lock picking sound.
Move faster
Hold (R) when walking to run.
Ducking
Hold (Analog-stick Down) to duck. This is useful when you are shooting out a window at a terrorist and he fires back, or if you need to get past a large window like that on the last level. Just duck and run to avoid getting shot.
Kill John Brightling
On the last level, Mystic Tiger, you can actually kill John Brightling. Once you reach the end of the level, throw a grenade at the window of the room he is in. The window will break and you can shoot him.
Submitted by: Barake
255 grenades
Change your weapon to the grenades and hold (Z] until the throw meter is filled .When the grenade is being thrown, hold (Z] again until the meter is full. Repeat until you are on the last grenade. When it is thrown, you will have 255 grenades. Note: This trick can be done with regular or flashbang grenades.
Unlimited ammunition
When using your main weapon, before you run out of ammunition change the magazine. Do this repeatedly to get unlimited ammunition. Note: Do not try this with the secondary weapon -- it will not work and your ammunition supply will slowly wear down.
Disable flashbang effect
Use the nightvision goggles after getting hit with a flashbang grenade to quickly restore your sight.
When you throw a flashbang grenade, wear your night vision goggles and you will not be affected.