Non-lethal ammunition is very important in the CIA HQ. You need to conserve it as best you can. The following steps start at the first place you should use it: After you enter the weapons room and disable the turret gun, take the elevator up and save at the checkpoint. Enter the room directly ahead of you. Once you are inside the room, stick to the right wall and sneak around back of the guard sitting at the computer. Behind the desk is a walkway which will allow you to sneak quietly around the room without confrontation. When you get towards the back door, wait for a guard to leave and then creep into the next room towards Daugherty's office. Once the area is clear, begin your walk towards the security camera at the end of the hall, then save the game. Wait until the camera turns away from you and use the first of your non-lethal ammunition (either the sticky shocker or foil ring) and knock out the guard sitting underneath the camera. When the camera turns away again, run underneath it and take aim at Daugherty, who is working with the soda machine. Shoot him with your second non-lethal weapon. Your headset will tell you it is a mistake, but it is easier this way. Drag the guard from the chair back to Daugherty's office --beware of the camera. Once you have hidden him. go back to Daugherty's body, again mindful of the camera. Grab his body and make your way for the door at the end of the hallway. Keep to the right side, crouched so that you can sneak past the break room window and then down to the keypad door. The code is "0614". This will bring you out to the smoking area, where there is still one guard out on the terrace. Again, use non-lethal weapon to knock him out and then hide his body. Then, pickup Daugherty again and bring him down to the next door and your final checkpoint. At this point you should have more than enough ammunition to shoot the four guards and the engineer non-lethally and easily escape the level.
DEFENSE MINISTRY/GETTING TO THE SOUTH/WING
After interrogating the driver and heading back upstairs, save at the checkpoint and view the intermission sequence of the window in the courtyard opening. Walk out on the balcony and turn left. Jump on the rain gutter on the wall. Move along the gutter towards the open window. If an alarm goes off, you have not properly hidden your dead bodies. Move back through the level and throw all your dead bodies into dark corners.
DEFENSE MINISTRY/NIKOLADZE'S OFFICE
Once you rappel through the glass window and kill the guard, access the computer in the far right corner of the level first. Then, access the main (Nikoladze's) computer closest to the window. Immediately run back to the window and drop out, but stay near to the ledge so that you will grab hold of it and hang out with the window. Guards will enter and search the office. They will not see you if you remain hanging out the window. They will clear the room, then leave. You can now access the computer again (as instructed by HQ). Then, proceed with caution when reaching your extraction point.
THE POLICE STATION
Sneak over to the right side to find something to climb to get on a shed. There is a trap door on top. Open it and go down it. Work your way around to find some pipes. Climb them as far as you can go, until you see a burning building. There is a slide wire here. Jump on it by pressing Y. Once inside the building, a woman will guide you .Do not go in the room in front of you . Go left down the hallway, then in a room, then back into the hallway. Go up the staircase. When there is a gap of fire, climb on a pipe above to get across. Once you get to a big room, the woman will tell you to go to some stairs in the opposite corner. Go up there in a room to find a man. He will talk. After that, leave through the only exit to find a room with smoke pouring out of it. Use your night vision in the room to find a door to go through. Save the game at this point. Then, go out the door and you will find a gap. Jump across it, then wait for the guard to get off the radio. Knock him out by grabbing him. Shoot out the two lights and go by the window on the right side. You can slide it open and press Y to jump in. Wait for the guard to open the door, then sneak up behind him and kill him. Go to the room with the keypad-locked door. As you enter the room, the first picture on the left can move. Move it and access the computer. The key to the door is 091772. Go on the balcony find the slide rope on the left. Use it to get to the roof. Work your way to find to the crooked cops. Wait for them to call for an ambulance, then grab the first man and shoot the other man. A civilian will report seeing you. Keep your hostage and kill the man around the corner. Then, dispose of your hostage. Go up the stairs. You should be in the courtyard area. Instead of shooting the lights, run to the far right corner. Stay ducked during all of this. In the bushes is a hidden area. Use the computer and get the med kits. Wait for the guard to come by, then shoot him in the head to conserve ammunition. .Proceed to the open gate. There is a drunk on the right. He will not attack, but try to grab him. If you let him see you, and he will run off. Grab him when you get close enough. Continue through the street. There is one guard around the corner and perhaps one more up ahead. Kill them and move on to find a lit area. Go to the far left and do a wall jump over the wall. Once inside, go down the stairs. The keypad on the door requires 5929 to be entered to gain access. Go inside and wait to kill the guard. Move all bodies you kill to somewhere dark where they will not be seen. Use the lock pick to open any locked doors and access all computers. There is a guard in the lab. Kill him. Carefully take out the camera in the morgue, then grab and interrogate the scared man. Do no knock him out yet. When he tells you nothing new, then knock him out. Walk up to the bodies on the tables. Lambert talks and you will keep going. Carefully walk through the door and kill the guard on the left. Let the other man go . Go into the room, use the computer, and get the med kit. Do not go out the double doors -- it is a waste of time. Go to the automatic door and walk up the stairs. Then, be quiet and sneak up on the first man and grab him. Take him to the dark area where you came from, then knock him out. Do the same to other man at the computer. Next, go to the door across from where the second computer man was located. Once inside you will see a silhouette. Go past the drapes, grab him, and knock him out. Access the computer to learn that you have completed the mission. Go out those double door that you passed earlier for extraction. Note: Always duck when you try grab someone because it is quieter.
SAVE AMMO
If you find a room being patrolled by a guard or worker, wait until he leaves, then turn off the light switch. When he returns, he will immediately move to the light switch to turn it on. At this point, his back should be turned to you. Quietly sneak up and either grab or punch him without firing your weapon.
RETRIEVING STICKY CAM
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.
ESCAPING ROOM FULL OF SOLDIERS
Take a sticky camera or smoke grenades and throw it near where the most guards are located. For the sticky camera, a control bar that tells you how to make a noise or use smoke will appear at the bottom of the screen. Throw the smoke grenade and the smoke should knock out some guards. When the smoke appears from the grenade(s), it is your chance to run for it.
KNOCK OUT AN ENEMY
To knock out an enemy without killing him, equip the sticky camera and shoot it at his head. Aim slightly above the head to compensate for gravity. After he is down, pick up the sticky camera and use it again.
LURING ENEMY
To do this, find a can or glass bottle to pick up. Once obtained, move to a location, preferably dark. While hidden, throw the can or bottle to an open area with an enemy nearby. When thrown, the enemy will wonder what happened and walk towards that location. After you have drawn him out, you can take him out for an easy kill.
HIDING BODIES
After you have disposed of enemies in an area, make sure that you still hide them, even though no one is nearby. Before going to another checkpoint, the alarm may ring, and it will say that a body was found. Try to hide all bodies in hidden areas for best results.