This level is pretty easy to do, unless you're gunning for Silent assassin. Before we start, there are two things you should know:
-The first objective to meet up with the contact at the first agency drop-point is not neccesary, you can ignore this and go straight for Agent Smith's location right away. This won't cause any problems. You can also go here at any later point in time.
-There is a man with a purple tulband and sunglasses marked as a civilian who'll run to you and eventually attack you. He's not actually a civilian, but it is recommended to avoid him if possible.
Meeting Agent Smith
First, go to your contact. He'll tell you where the exit is. After you meet him, Agent Smith's location will be marked on the map as a second agency drop-point. You may skip this point as both Agent Smith and the exit can be found without his help and the game doesn't fuzz about skipping this point. It is recommended that you do NOT take the SP12, you cannot holster it and will be attacked on sight. If you want the gun, you might be able to get to the exit point unseen once you're done with the objectives. There is also a second SP12 hidden north of the pick-up point.
After the cutscene, the location of Agent Smith will appear on the map. This will be a randomly generated location. Go there, Agent smith will panick and shoot in the air with his Deagle before starting the cutscene, this shouldn't alert anyone unless you're unlucky. It might be possible to avoid this by picking the lock of the back door, although this wasn't possible on v1.0. Smith will give you a camera and tell you to kill the two assassins lurking around looking for you. You'll have to take a picture of their corpses and show it to him before he'll leave his hide-out.(He won't actually leave it during the level.)
Killing the assassins
There are two assassins which will now appear on the map as enemies. The third assassin marked as a civilian will appear now too, you won't have to photograph his dead body.
Let's start with the easy part: Kill the sniper. Walk by the building where the sniper is and stop when you are just ahead of him on the map. Get into the shop to your left/right. Thanks to the alleyways around the squares it is very easy to get near him unseen regardless of which direction you come from. Do not let the other assassins: Blue Cap or Purple Turban see you.
Sneak up the stairs and into the room where the sniper is. Fiberwire him and take his photograph. You can choose to take his R93 and shoot Blue cap, but this will make taking the picture more difficult. You can also take his uniform, but this won't fool either of the assassins and will make the other cultists a bit more suspicious. You might want to drag the body slightly back to the stairs to avoid panicking civilians.
There are two ways to kill Blue cap: -Come out and let Blue Cap see you. Lead him into a deserted spot and hide somewhere with a silenced pistol in hand. Blue Cap will turn back. Shoot him and photograph his body. [NOTE: Here, somehow Purple Turban sees me and there is a shootout and then...goodbye, Silent Assassin rating] -Hide behind a pillar and shoot Blue cap while he walks by. It is possible, though very difficult, to do this without any civilians seeing you (shoot him exactly right so that the pillar covers the view.) Considering the tight window of opportunity, this is pretty much impossible with the fibre wire. In fact, don't worry about the civilians, just make sure there aren't any cultists nearby to see it. You can drag his body into one of the stores, it won't be found if you drag it to the space behind the stairs.
Finish the mission
Get back to Agent Smith. Wait around for some time - it is possible that Purple Turban comes to kill him, wait and kill Purple Turban before he gets the chance. If he kills Smith, it's game over. It is possible for this not to happen, and neccesary if you want a Silent Assassin rating. You might also fibre wire purple turban before this point, it is possible with the same technique as killing blue cap #2.
You may want to pick up the SP12 now, it is relatively easy to get to the exit unseen while open carrying when using the alleyways and the map.
Now go to your exit. Enter the shop QUICKLY - a sniper is watching the door. The exit is behind a carpet against a wall. Off course, you may kill the sniper and his companion if you want to. If you shoot the sniper from a distance (with a silenced gun, unsilenced not tested), the other agent won't react. You can also sneak up on them and take the ladder up.
If you bring your silenced pistol and work fast, it is possible to get a professional rating by running around and shooting cultists in the back of the head whenever they are in the alleyways. Due to the ample cover and ability to hide whenever people check on their fallen collegues, you can kill them all before people even get alarmed. (normal mode) Do this before talking to Agent Smith and you can prevent Purple Tulband and Blue cap being a problem because they won't have any back-up.