Complete Assassin's Creed.
Complete all 9 assassinations
Complete the last mission

Kill every Templar.
Throughout the game there are 60 Templars and the majority of them lay within the kingdom. All you need to do is kill every single one of them.

Locations:

30 - Kingdom
03 - Dasmascus poor
03 - Dasmascus middle
04 - Dasmascus rich
04 - Acre poor
03 - Acre middle
03 - Acre rich
03 - Jerusalem poor
03 - Jerusalem middle
04 - Jerusalem rich
** See individual flag maps for locations of templars (green dots) **

Find All of Richard's Flags in the Kingdom.
There are 100 flags of Richard in the Kingdom.

Locations:

100 - Kingdom

Find All Flags in Masyaf.
There are 20 flags to find in Masyaf.

Locations:

20 - Masyaf

Find All Flags in Jerusalem.
There are a total of 100 flags/crosses to find in Jerusalem.

Locations:

34 - Poor
33 - Middle
33 - Rich

Find All Flags in Damascus.
There are a total of 100 flags to find in Damascus.

Locations:

33 - Poor
34 - Middle
33 - Rich

Have a complete Synchronization bar.
Sychronization increases as you:

Rescue citizens
Visit View Points
Get ranks reinstated by Al Mualim after you've completed assassinations.
If you complete everything as you go along, this should unlock around your 8th assassination.

Complete all Reach High Points.
There are a total of 91 high points (view points) in the game. Climb to the top of them and press Y to synchronize.

Locations:

12 - Kingdom
09 - Dasmascus poor
07 - Dasmascus middle
10 - Dasmascus rich
11 - Acre poor
09 - Acre middle
11 - Acre rich
06 - Jerusalem poor
07 - Jerusalem middle
09 - Jerusalem rich

See 85% of all the memory glitches.
During the majority of cut scenes while you're playing as Altair, you will sometimes see the screen 'glitch'. You will see a bunch of hexagon-shaped molecule diagrams flash quickly on the screen.

Pressing any button will make the scene cut to another camera angle. These are the glitches.
Constantly tapping any button during every cut scene will make sure you hit at least 85% of the glitches.
If you get every glitch, this achievement should unlock during the cutscenes for the 8th assassination

Complete every free mission in Acre.
Just save every civilian in the poor, middle and rich districts of Acre:

12 - Acre poor
12 - Acre middle
12 - Acre rich

Complete every free mission in Jerusalem.
Just save every civilian in the poor, middle and rich districts of Jerusalem:

12 - Jerusalem poor
12 - Jerusalem middle
12 - Jerusalem rich

Complete every free mission in Damascus.
Just save every civilian in the poor, middle and rich districts of Damascus:

12 - Dasmascus poor
12 - Dasmascus middle
12 - Dasmascus rich

Go through every dialog with Lucy.
Whenever you finish a memory block, you will be asked to rest.

Wait until the doctor has left the room
Stand next to Lucy and press B when the prompt appears
Continue to press B every time the conversation finishes
When she says "Aren't you tired?" and "Sorry can't talk, got work to do" then you may go and rest
You will not get a chance to go back and get missed conversations after you go to sleep. MAKE SURE you get these.

Assassinate all your targets with a full DNA bar.
Widely accepted and believed to be unlocked by:

"The DNA bar is the bar that fills up as you complete the investigation missions in each memory block. In order to get this achievement, simply complete all six investigations for each assassination rather then stop after three."


"Again, this achievement really only requires awareness and patience. You need to assassinate every target with a full DNA (health) bar, not just kill them in open combat. Make sure every assassination is a one-hit kill with your hidden blade. This doesn't mean that every assassination must be a low-profile hidden-blade attack though. Holding down X for a hidden-blade strike for a high-profile assassination will still score this achievement."

As it says you must defeat 100 opponents without dying.

Tips:

Spend the majority of your time blocking.
Always try and counter kill them as it is a lot easier.
Run around the city killing every guard you see.
If you are having trouble, this glitch works for some reason:
At the start of the game in Masyaf, run along the far left side of the village until you see a spiked outcrop pointing up toward the mountain with a tree just in front. If you run into the corner at the point while moving left and right, you'll be able to wriggle up the cliff face. When you reach the top, jump off the edge of the map and you'll unlock the achievement!

Last 10 minutes in open conflict.
This one is a lot easier than it sounds.

Attack a guard
If there is more than one, kill them until only one remains
Sit back holding block (RT)

Assassinate 100 guards.
You need to assassinate 100 guards. It doesnt matter whether they are attacking you or not, but as a general rule, most of the time they will block you if they are aware of your intentions.

Press UP to equip your hidden blade, and press X while next to a guard to assassinate them.

Kill one of your main targets like a true assassin.
This has to be done on one of the main 9 targets.

To kill like a true assassin the tagret must not be aware that they are about to die.

Walk up to your target holding A in low profile to blend.
When you're next to your target (still holding A ), hold X to assassinate your target.
Tron Advice: It's easiest to do this on the first target.

Defeat 25 guards in a single fight.
A single fight means that your synchronization bar must remain red throughout the entire fight.

Attack a guard and hold block. Keep backing away around the town and gather a group of guards. The max I could get at once was 13. Once you've gathered the maximum (again 13 for me), kill them until one remains. Then gather another group and kill that twelve. I find it's safer to gather a third group and then kill them all. This makes sure you actually got 25 instead of 24.

Always keep one guard alive
Always keep synchronization bar at red

Perform 100 Counter Kill in Fights.
You need to counter kill 100 opponents in fights. This doesn't need to be done in one go, but is specific to your game file.

Wait for your opponent to step towards you to begin his attack
Just before he hits you, press X and you will counter him and kill him
Sometimes you won't kill him and just kick him away, this doesnt count towards the achievement.

Perform 50 Combo Kills in Fights.
Combo kills are frustrating and take a lot of precision timing. Luckily you only need to get 50 of them this time.

While fighting, press X to attack someone, the split second your sword makes contact with theirs, press X again to combo kill them.
Constantly pressing X until you kill them doesnt count as a combo kill
If you're having trouble with pulling off a combo kill, you can practice them in the courtyard in Masyaf

Perform 50 stealth assassinations.
A stealth assassination is an assassination without alerting the guard to your presence

This is best pulled off on guards on the rooftops and guarding doorways.
Press UP to equip your hidden blade, slowly walk up behind the guard and press X to stealth assassinate them.

Perform 50 leap of faith.
A leap of faith is when you jump from a high point into a stack of hay below. You perform one of these in the attack on Masyaf.

Hold RT , A and forward to jump off into a stack of hay
You can do leaps of faith mainly off view points, but there are a few other locations.
Some locations require very little time to climb to the top again, meaning you can just repeat it off that point 50 times. A good example is in the west of Masyaf

Pickpocket 200 throwing knives.
You may notice while walking around, some fat looking men wearing brown leather outfits with knives on their belt.

Target onto them with LT the and hold B to pickpocket their knives.
This is easiest done later on in the game when your max amount of knives is at 15.
Just keep pickpocketing until you've stolen 200.

Use Scholar blending 20 times.
Blend in and out of the same group of scholars 20 times.

Walk up to a group of scholars (a group of 4 guys in white robes), press A to blend and A again to blend out. Just follow the group and repeat 20 times.

Kill 75 guards by throwing knives.
You need to kill 75 guards with throwing knives.

Stand far from the target
Press Left to select the throwing knives, Lock onto the target with the LT and press X
If you run out of knives, steal some more

Grab and Throw 25 Harassers.
You will sometimes find a beggar run up to you and harass you for food, money etc.

Hold the RT and press B to grab them. Once you've grabbed the beggars, throw them away.
The beggars must be different people
Sometimes you'll find a crazy person attacking you. Grabbing the attackers won't scare them and neither will it contribute to this achievement.

Jump through 20 merchant stands.
Find a merchant stand and jump through the stand 20 times

Press RT , A and forward to jump through the stand

Find All Teutonic Flags in Acre.
Find all the teutonic flags in the middle district of Acre.

33 flags in the middle district

Find all Templar Flags in Acre.
Find all the Templar flags in the rich district of Acre.

34 flags in the rich district

Find All Hospitalier Flags in Acre.
Find all the Hospitalier flags in the poor district of Acre

33 flags in the poor district

A strange vision has appeared to you. What could it mean?
Storyline, so you won't miss it.

You've slain Tamir, Black Market Merchant in Damascus.
Storyline, so you won't miss it.

Assassinate Tamir.

You kill him in Memory Block 2

You've slain Talal, Slave Trader of Jerusalem.
Storyline, so you won't miss it.

Assassinate Talal.

You kill him in Memory Block 3

You've slain Garnier de Naplouse, Hospitlier Leader in Acre.
Storyline, so you won't miss it.

Assassinate Garnier.

You kill him in Memory Block 3

You've slain Majd Addin, Regent of Jerusalem.
Storyline, so you won't miss it.

Assassinate Majd Addin.

You kill him in Memory Block 4

You've slain Abul Nuqoud, Merchant King of Damascus.
Storyline, so you won't miss it.

Assassinate Abul Nuquod.

You kill him in Memory Block 4

You've slain William of Montferrat, Liege-Lord of Acre.
Storyline, so you won't miss it.

Assassinate Willian of Montferrat.

You kill him in Memory Block 4

You've slain Jubair, the Scribe of Damascus.
Storyline, so you won't miss it.

Assassinate Jubair.

You kill him in Memory Block 5

You've slain Sibrand, the Teutonic Leader of Acre.
Storyline, so you won't miss it.

Assassinate Sibrand.

You kill him in Memory Block 5

You've slain Robert de Sable, but there is one more... (7)
Storyline, so you won't miss it.

Assassinate Robert de Sable.

You kill him in Memory Block 6

You've successfully completed the Animus tutorial.
Storyline, so you won't miss it.

Just complete the tutorial.

Its the very first thing you do

You've protected Masyaf from the Templar invasion.
Storyline, so you won't miss it.

Protect Masyaf from the Invasion

Run out of the castle into the town, kill all the enemy guards while making your way down to the gates

You have found the traitor and have brought him before Al Mualim.
Storyline so you won't miss it.

Find the traitor and bring him to the leader.

The first mission that your leader sends you on. Just gather information and find the traitor in Masyaf