After killing Al Muaiam and returning to the real world, listen to the conversation about how they going to kill you. Turn on your Eagle Vision, and look at the floor. There are some mixed up letters on both sides of the Amnius. You should see on the side closest to the main door:
M O R Y M N O E S E N C E O L C H T H O N B T L O T C T D E O S A T O A P E D S N L S T F L D D U O O E T E E A I E I R I N T H S H K T T K E R T U A A A N S S A
To decode this, start reading at the bottom right hand corner to the top right hand corner, so you will start at "A" and stop at "S". It will spell a real word. Do this for all of the columns and it will read:
ARTEFACTS SENT TO THE SKIES TO CONTROL ALL NATIONS TO MAKE US OBEY A HIDDEN CRUSADE DO NOT HELP THEM
Next, do the same thing to the mixed letters on the other side of the Amnius:
A D R H O O D T M W H B I T D O E U S Y S I N S E A R O O M R E A Y N R I S E Y T N I D L M I D E T W I H W Y I E A U D A Y H T
It will spell out:
THEY DRAINED MY SOUL AND MADE IT THEIRS I DRAINED MY BODY TO SHOW YOU WHERE I SAW IT
Go into any of the main cities, preferably Damascus (Poor District), and find a merchant stand. Start hopping through it. If you can find two that are next to each other, it saves time. Keep jumping through the merchant stand(s) until you get the achievement.
Travel to the southwestern-most vigilantes in the poor district of Damascus. On one of the buildings around them is a outcropping in the wall. Climb on it and you will see that it looks exactly like G1 Optimus Prime in vehicle mode. Note that there may be more than one outcropping in the area, so look carefully. If you lose sight of the vigilantes, you have gone too far. Also, these types of structures can be found throughout the poor district.
After the credits, you can look at all the computers and drawings and what not, but on Lucy's computer, there is a specific message crucial to the meaning of "The Leak." This means that there are more assassins.
When you log on to Lucy's computer by the animus bed, go to her deleted message, the first part you will read looks like an advertisement for some sort of enhancement, but in the text there are capital letters reading,
1. Always lock on to your target. 2. After your lock on you just need to get not too far and not too close to your pickpocket target 3. While you're walking to your target hold the pickpocket button (you will have your hand out so don't bump into anybody, you might just steal from them or something) 4. Now that your hand is out, just keep on walking slowly until you get to the belt of the target (there is a pouch on the belt that it helps to aim for).
To easily defeat a Templar, press L2 to lock on to him and quickly equip the hidden blade. Wait for him to attack you so that you can counter attack and kill him in one blow. This is better than the sword fight. If you counter with the sword, you will only knock him down and not kill the Templar.
To access the conference room, after the credits show up at the end of the game you'll receive an access code for the computer at the Animus. Once you crack the computer, you'll see an inbox, outbox and deleted message. Look at the inbox and select the entry regarding the conference room. Now you can go to the conference room and access it using the keypad.
To get easy kills, equip your hidden blade and throw an enemy to the ground. While they are lying on the ground, stab them. This is especially useful when surrounded by enemies or when assassinating targets.
Note: Only attempt this technique if you are skilled in the Rank 2 skill "Counter" and have enough Synchronization bars; one and a half rows of bars are enough. During battle, equip your hidden blade. With this is equipped, all of your counters will score an instant kill. You can even instantly kill tougher ranked guards (such as the Teutonic guards in Acre when hunting Sebrand). Also, most of the time, using the hidden blade in battle will scare the last one or two guards, causing them to run away. However, since you do not have a weapon that is sufficient enough to block a full sized enemy blade, all incoming attacks will hurt you.
During battle, if you see a guard you are fighting physically emote in any way, press Low Profile Assassinate while facing them to score an instant kill without the need to counter.
The best weapon when facing four guards or thugs is the Short Blade.
When you go to bed after Memory Block 2, you will notice your closet door is open. Press any button to get a piece of paper Desmond notes as a code. The code will unlock your bedroom door, which allows you to go out as often as you like after you go to bed, as well as to open the meeting room area. You can also pick up various items to unlock Lucy's password.
Complete the game and watch the entire credits. You will be given the access code for the computer attached to the Animus. Hack the computer to access an inbox, outbox, and deleted message. Look at the inbox and select the email about the conference room. You can go to the conference room and access it via the keypad.
In Memory Block 1, after Al Mualim sends you to defend the fortress against the Templar attack, wait at the intersection/fork that is about 135 feet from the destination, just after the hill/path that leads to the Creed building. Guards will repeatedly respawn down the right fork. Just stand still and kill 25 guards as your status will never leave "exposed", until you go to the destination.
Go to the entrance of Acre, but go through Kingdom. Find the base of soldiers and start killing them, but do not finish all of them. Instead, start running to gather more. Kill a couple and run again. Do this until you get the achievement. If you take long you may also unlock the "Eagle's Flight" achievement.
In Masyaf, go to the castle and enter the training arena, then select the option for combo kill. When you succeed three times the match will end. Select it again and continue until the achievement is unlocked.
There are three computers, two in the main room and one in the conference room. To access Lucy's computer, go to the computer on the anumus and pick up the pen beside it. To access Vidics, steal the pen that is in his pocket when you see him earlier in the game. Read all emails on both computer including the ones in the deleted section. After reading them, you can access the computer in the conference room.
When trying to "save a citizen", run in, assassinate one guard with your hidden blade, lock onto the closest guard, and hold R1. When the guard comes in to attack, press SQUARE to parry and kill the guard in one smooth, clean move. Repeat this for all guards to avoid taking damage.
The Master will take away your ability to use radar and make it hard to see. This also allows him to hit you once and kill you. Lock on to him and use a throwing knife against him. This will take away his power to blind you and make him easier to kill.
The first part is simple. Take out your sword and fight all your previous assassination targets. They are fairly easy to kill. Only one counter is required to kill each of them. For the second part, as soon as Al Mualim releases you, use your Eagle Vision to spot the real Al Mualim--the one in yellow. Focus your attacks on him. In the third part, Al Mualim takes away your synchronization bar and radar, allowing him to kill you in one hit. Take out your throwing knives and look for the Piece of Eden in his hand. Once you see him, throw a knife at him. Then, just counterattack/grab break him. Repeat this until he says, "Damn you Altair!" Finish him off with your hidden blade or keep attacking him with your sword until he is dead.
Equip either the short blade or the sword and, when facing a large number of guards, just keep attacking them, bouncing one attack to one enemy then attacking the next. If one of the enemies tries to attack you while attacking another guard, immediately press X. This will allow you to attack while rapidly countering enemies. Another way is when the enemy dodges your attack then follows-up another attack. Do the same thing, but make sure your timing is good enough to allow you to survive even if there are six or more guards.
When you first reach Damascus and have to save the citizen, kill two of the three guards. Back yourself into a stall or a corner that you cannot be pushed out of and hold RT to guard. In ten minutes you will have the achievement. You can also put a rubber band around your controller and LT and allow the game to idle.
To easily defeat William of Montferrat in Acre, after the guards leave William, drop down from the castle and kill William. Then, "de-target" or deselect and run up into the castle buildings and battlement to escape.
Complete these in the following order to decrease the difficulty ofeach major assassination and lower the time needed to complete the game:
1. Visit Assassin's Guild.
2. Scan the city by first climbing all of the view points.
3. Rescue all citizens from the thugs.
4. Complete all of the informant's missions
5. Pickpocket the shysters in all of the pickpocket missions
6. Go back to the Assassin's Guild and get ready for the major assassination mission.
After getting the "target" to a safe area to "interrogate" them, punch them first, then "grab" them for faster completions. It will take about two grabs to quickly finish them. However, in the last three quarters of the game, you might have to grab them up to four times.
This achievement is easiest to unlock in Damascus. Save the citizen in front of the main gates if you have not already done so, then go to the scholars. Blend in with them. As they get past the main array of guards, start pressing repeatedly. You should be going in and out of blend mode continuously. After a short time you should get the achievement.
When you first reach Damascus after saving the citizen, you will learn how to blend with scholars. Enter this blend and exit it twenty times rapidly to unlock the achievement.