Keypad Codes:

Mission 1 - Police Station
Keypad #1: 091772
Keypad #2: 5929


Mission 4 - CIA HQ
Keypad #1: 7687
Keypad #2: 110598
Keypad #3: 2019
Keypad #4: 110700
Keypad #5: 0614


Mission 5 - Kalinatek
Keypad #1: 97531
Keypad #2: 33575
Keypad #3: 1250


Mission 8 - Chinese Embassy, Part II
Keypad #1: 1436
Keypad #2: 9753
Keypad #3: 1456
Keypad #4: 1834
Keypad #5: 7921


Mission 9 - Presidential Palace
Keypad #1: 2126
Keypad #2: 70021
Keypad #3: 66768

Training Stage Secret:
In the Training Stage, after you complete the task of looking at the lights, go over to the left or right. You will be above the lights and should find two doors. On the right is a door that leads to a room where a lock pick is sitting on the shelf. You can use this to get into the other door leading to the covert-ops section of the training. After entering this room and getting the keypad code (5656), you can then go left and get into the doorway to the left of the start of the level. You'll find two rooms. In the last room is Anna Gromsdottir. You can talk to her about different things, but DON'T hit her because you will be fired!

Faster manual lockpick:
When using the manual lockpick, instead of rotating it slowly as the game suggests, press the stick in one of the four diagonal corners, as the "rumble" will always be in one of those directions.

Retrieving Sticky Camera:
To retrieve a Sticky Camera that is too high to reach, shoot it with the sniper rifle or the handgun. It will fall to the ground.

Sticky Camera Knockout:
This does not work until after you have found the SC-20K and have Sticky Cameras. If you are close to an enemy and want to knock him out, shoot him in the head with a Sticky Camera. It will knock out your enemy, and you can then pick the camera up off of the ground.

Thermal goggle keypad readings:
To read the heat signature on a keypad, you can either walk up to the keypad and look at it with the heat goggles on, use sniper mode at a distance with the heat goggles on, or activate the keypad and turn on your heat goggles there. The order of the buttons is based on color: Deep Blue, Blue, Light Blue, Green, Light Green, Yellow, Orange, Red. For example, if you had a Deep Blue button at 1, a Light Green button at 3, a Light Blue button at 4, and an Orange button at 6, the code would be 1-4-3-6.

Thanks to Revolution readers Barney Russel, Martin Brodeur, Fance45 and john!