At the start of a level, tap up, up, down, down, and hold A for 8 seconds.
Chinese Embassy 2
When you come to the room with the sleeping guards you can avoid two of the guards by not continuing on to the next room, but instead, pick up the med kit, ammo, and frag grenade and go back the way you came in. Continue to the door at the end of the hall. On the left the code for the door is 1436.
The game now bypasses a part where two guards come and open the door. This way you never see those two guards - the part after it will have you stressed out enough as it is
CIA HQ level
On the level CIA HQ, when you get further there will be some big windows with someone guarding. Be careful not to trigger any alarms, get a sticky shocker and move slightly from the left side of the window so that you can see him, then shoot him. You will knock him out without him knowing.
Lights
Shoot the lights when no one is around to make it dark. Enemies cannot see you in the darkness
Taking out lights without ammo
First get a object Glass bottle. Then Walk up to a light, Press L then throw it at the light.
Throw harder
Hold L when tossing cans and bottles to throw it harder.
Using Flares
You can use flares to distract turrets and the like momentarily when they are causing you strife.
Mission 1 codes
The first lock code is: 091772 The second lock code is: 5929
Mission 4 codes
First lock code: 7687 Second lock code: 110598 Third lock code: 2019 Fourth lock code: 110700 Fifth lock code: 0614
Mission 5 codes
First lock code: 97531 Second lock code: 33575 Third lock code: 1250
Mission 8 codes
First lock code: 1436 Second lock code: 9753 Third lock code: 1456 Fourth lock code: 1834 Fifth lock code: 7921
MEET GRIMSDOTTR
In the very beginning of the game on the very first level, Lambert briefs you about Third Echelon, then sends you to an assault course. once he's done blabbing about red lights, he tells you to jump over a wall. Don't do it. go to you'r immediate right and double jump up on to the ledge. Once on the ledge look to your right once more. There is a door, and behind it is a closet or janitor's room with some shelves to your left. On those shelves is a pair of lock picks. Pick them up and go all the way to the end of the course, but don't finish it. Instead of going through that meatal hangar door, go to the right of it. There is another wooden door that is locked. Pick the lock and use the computer in that small room. It will give you a code for a servailance platform or something. That room is all the way at the beginning of the course to your left. where the room was with the lock picks, but on the other ledge. Go up that ledge and there you will find a door that is keypad locked. Use the code you got from the computer to get in. I could have told you the code, but what would the fun be in that? Behind that door is a small room with a doorway in front of you. Go through the doorway and Grim is to your left. You can talk to her, and she'll give you a litte more info on what you're doing here. Submitted by Bob Williams