At first glance through the levels you may not see things that can help. For example, there are many pipes that let you climb on. If you hide up there and the guards in the black do not see you, move along the pipe and they will not shot you. You can also hide behind items that appear to be up along the wall (lockers, plants, curtains, plants boxes, and other items). However, if one of the guards sees you go behind them to hide, he will hit the alarm more then once. Normally if you hide long enough the alarm will stop. Also if the guards in the level stop and hit the alarm and see you, run behind something. If the guard stands there, you are in trouble; when the guards that are in black see the other guard, they will stop and throw bombs to flush you out.
When the objective to meet the women at the docks appears, you can shoot the enemies on your way out. You can also shoot the cameras during the first part.
The codes for the first two computers that require you to choose numbers are as follows. The first code on the top is 1001, the bottom is 0010 or 2 and 9. The second code is 0110 on the top and 1000. On the bottom. Note: You cannot kill the men by the computers. You still must grab them from the back, walk in front of the computers, and press Up.
Finding the women in Embassy 1 level is easy if you wear your thermal goggles when you must laser mic her so she can tell you where she is.
When in the subway and you are in the rooms that are dark, you can see the bombs on the wall and on the ground and boxes by wearing the thermal goggles.