This is a list of what is required for 100% Sync in the main retail game complete with youtube videos for every mission I could find.
If you guys come across any dead links, please let me know asap and I will update!
Please refer to xThe Amory Wars solution for DLC Sync.
Please see the bottom of this guide for some additional tips.
I just finished getting 100% sync in Assassins Creed: Brotherhood and I can confirm that for 100% sync in the main retail game you need to get:
100% Sync in each of the main story sequences (1-9)Sequence 1:-Mass Exodus
***No Sync
-Homecoming
***No Sync
-R&R
***No Sync
-Horsing Around
***No Sync
-Target Practice
***No Sync
-Reunion
***No Sync
-Vilified
***No Sync
-Emergency Exit
***No Sync
Sequence 2:-As good as new...
***Do not drop below 1 health square
-Well Executed
***Kill your target with the hidden blade
-New Man In Town
***Throw the Borgia Captain into the scaffold to kill him
-Easy Come, Easy Go
***Dont lose any health
-Who's Got Mail?
***Catch the Borgia Courier in under 1 minute
-Crepi Il Lupo
***Dont lose any health
-The Halls Of Nero
***Complete the memory within 8 minutes
-Roman Underground
***No Sync
Sequence 3:-Double Agent
***Do not be detected while reducing Notoriety. Remain undetected until rejoining La Volpe at the Thieves Guild
-Between A Rock And A Hard Place
***Kill only the Borgia Captain
-High-Stakes Negotiation
***Do Not Swim
-Collective Intelligence
***No Sync
Sequence 4:-Castello Crasher
***Do Not be detected
-Femme Fatale
***Do not lose more than 10 health squares
-The Burdens We Carry
***Do not be detected
-Gaurdian Of Forli
***Achieve a kill streak of atleast 5 gaurds
-Man Of The People
***Do not lose more than 5 health squares
-Serial Offender
***Kill your target using the assassin recruits
-Human Cargo
***Kill your target using the assassin recruits
-An Unexpected Visitor
***No Sync
-The Plan
***No Sync
Sequence 5:-Escape From Debt
***Do not be detected whilst escorting the senator
-Follow The Money
***Do not be detected and do not touch the ground whilst escorting the senator
-When In Rome...
***Arrive at your destination in less than 3 minutes
-In And Out
***Kill the banker from a bench without being detected
-Paper Trail
***No Sync
Sequence 6:-Gatekeeper
***Do not take any damage
-French Kiss
***Do not be detected
-Trojan Horse
***Do not lose any health squares
-Au Revoir
***Finish the mission in less than 5 minutes
Sequence 7:-Patching The Leak
***Do not drop below 5 health squares
-Calling All Stand-Ins
***Use the assassin recruits to kill your targets
-Exit Stage Right
***Do not kill anyone other than the gunmen
-Intervention
***Do not swim
-Ascension
***No Sync
Sequence 8-Requiem
***Do not be detected
-An Apple A Day
***Do not kill anyone
-The Apple Of Eden
***Do not lose any health
-Demilitarization
***No Sync
-Seeing Red
***No Sync
-All Roads Lead To...
***No Sync
Sequence 9-Pax Romana
***Do not drop below 5 health squares
-A Seed
***No Sync
100% Sync in each of the secondary memories:Secret Locations/Romulus Lairs:-Wolves Among The Dead
***Complete the memory within 8 minutes
-Thrown To The Wolves
***Do not lose more than 3 blocks of health
-Leader of The Pack
***Do not lose more than 10 health squares
-The Sixth Day
***Do not lose more than a block of health
-A Wolf In Sheep's Clothing
***Complete the memory within 8 minutes
War Machines:-War Plans
*** Send The Mercenaries Into a Fight
-Outgunned
*** Do not kill anybody before destroying the blueprints
-War Plans
***Use the kick against the Overseer
-Loose Cannon
***Open 1 of the first 3 gates
-War Plans
***Use a smoke bomb to stun the Overseer
-Flying Machine 2.0
***Do not get shot whilst using the bomber
-War Plans
***Use the pistol to kill the Overseer
-Hell On Wheels
***Do not take damage while in the tank
-Templar Agents:-Down To Earth
***Kill your target with the hidden blade
-Counter-Propaganda
***Kill your target with the hidden blade
-Excommunication
***Kill Brother Ristoro by air assassination
-Firing Line
***Kill the target using the hidden blade within 45 seconds
-Red-Handed
***Kill your target with the hidden blade
-The Ringer
***Kill only Don Machini
As of 04/11/11 I could not find suitable YouTube videos for the remaining mission types.
For the following missions use this guide, which include videos:
https://www.ign.com/wikis/assassins-creed-brotherhood/Side_M...-Assassination:-Two's Company
https://www.ign.com/wikis/assassins-creed-brotherhood/Two%27...***Kill both targets with your hidden blade
-Tactical Correction
https://www.ign.com/wikis/assassins-creed-brotherhood/Tactic...***Finish the memory within 2 minutes
-...And Three's A Crowd
https://www.ign.com/wikis/assassins-creed-brotherhood/And_Th...***Kill the 3 targets within 2 minutes
-Serf's Turf
https://www.ign.com/wikis/assassins-creed-brotherhood/Serf%2...***Assassinate the 3 guards with the hidden blade
-The Three Amici
https://www.ign.com/wikis/assassins-creed-brotherhood/The_Th...***Kill the targets with the hidden blade
-Red Letter Day
https://www.ign.com/wikis/assassins-creed-brotherhood/Red_Le...***Kill both targets in under 60 seconds
-The Merchant Of Rome
https://www.ign.com/wikis/assassins-creed-brotherhood/The_Me...***Use the assassin recruits to assist in a diversion
-Bearers Of Bad News
https://www.ign.com/wikis/assassins-creed-brotherhood/Bearer...***Do not let your targets call for reinforcements
-Cardinal Sin
https://www.ign.com/wikis/assassins-creed-brotherhood/Cardin...***Kill only the cardinal
-Turning The Tables
https://www.ign.com/wikis/assassins-creed-brotherhood/Turnin...***Kill atleast 1 brute, 1 seeker, and 1 papal guard with his own weapon
-Graduation
https://www.ign.com/wikis/assassins-creed-brotherhood/Gradua...***Do not lose any health squares
-Brutes and Brutality
https://www.ign.com/wikis/assassins-creed-brotherhood/Brutes...***Kill all targets in under 15 seconds
-Thief:-Lost Pup
https://www.ign.com/wikis/assassins-creed-brotherhood/Lost_P...***Save Aldo in under 2 minutes
-A Clash Of Interests
https://www.ign.com/wikis/assassins-creed-brotherhood/A_Clas...***Survive the fight without any thieves being knocked out
-Up To Speed
https://www.ign.com/wikis/assassins-creed-brotherhood/Up_to_...***Complete the course in under 60 seconds
-Class Warfare
https://www.ign.com/wikis/assassins-creed-brotherhood/Class_...***Kill all of the bandits with the pistol
-Pointing Fingers
https://www.ign.com/wikis/assassins-creed-brotherhood/Pointi...***Remain undetected
-Eye On The Prize
https://www.ign.com/wikis/assassins-creed-brotherhood/Eye_on...***Remain undetected whilst attempting to steal the contents of the box
-Young At Heart
https://www.ign.com/wikis/assassins-creed-brotherhood/Young_...***Complete the course in under 60 seconds
-Downsizing
https://www.ign.com/wikis/assassins-creed-brotherhood/Downsi...***Kill the traitor with the hidden blade
-A Blanket Finish
https://www.ign.com/wikis/assassins-creed-brotherhood/A_Blan...***Kill the Cento Occhi leaders with the hidden blade
-For The Fans
https://www.ign.com/wikis/assassins-creed-brotherhood/For_th...***Complete the course without taking any damage
-Courtesan:-Property Dispute
https://www.ign.com/wikis/assassins-creed-brotherhood/Proper...***Stop Santino before he beats up the Courtesan
-Old Habits Die Hard
https://www.ign.com/wikis/assassins-creed-brotherhood/Old_Ha...***Assassinate the target from a hiding spot
-The Morning After
https://www.ign.com/wikis/assassins-creed-brotherhood/The_Mo...***Complete the mission in under 400 seconds - random right?!
-Running Scared
https://www.ign.com/wikis/assassins-creed-brotherhood/Runnin...***Kill only the ambassador
-Live Bait
https://www.ign.com/wikis/assassins-creed-brotherhood/Live_B...***Kill the target using the ledge grab
-Malpractice
https://www.ign.com/wikis/assassins-creed-brotherhood/Malpra...***Do not kill the doctor
-Closing In
https://www.ign.com/wikis/assassins-creed-brotherhood/Closin...***Kill the target using the hidden blade
-Bad Politics
https://www.ign.com/wikis/assassins-creed-brotherhood/Bad_Po...***Kill all targets in under 60 seconds
-Troublemakers
https://www.ign.com/wikis/assassins-creed-brotherhood/Troubl...***Finish the mission with both mercenaries above half health
-Ghostwriting
https://www.ign.com/wikis/assassins-creed-brotherhood/Ghostw...***Complete the mission in under 2 minutes and 20 seconds.
Thanks to the following users for their YouTube videos:
RE5LEGEND
IGN
RedLightGamers
LegendaryMate
TheMediaCows
WikiGameGuides
AFGuidesHD
Bikerbob12
ADDITIONAL TIPS:-Thanks to Crosby v2 - For all those, who have got some problems with Da Vinci's Tank-Mission:
Instead of doing it the way you're supposed to, there is also a lot cheaper way to get the full sync in this mission. All you have to do is, right when you crossed the final gate, shoot the "cover" in front of the right tank, then immediately go behind the white Desynhcro wall (it's behind you, the direction you came from) and stop right at your 1st warning. Just stay there and keep firing at them. As they are not able to hit you, it shouldn't be a problem to get the 100%
-Thanks to Weezleram - If you change your outfit you will revert back to the previous checkpoint. This is VERY useful for some of the memories, if the memory is long and you are about to lose your full sync condition just pause and change your outfit so you won't have to replay the entire memory. This is highly recommended for the Hell on Wheels memory (if you won't be able to get out of the way of a cannon/tank shot you can simply revert to the last checkpoint instead of starting the entire memory over.
-Another Tip: If you appear to be missing some Sync % still, you need to activate the courtesans and thieves missions by visiting the associated guild. It wont show up at all otherwise. I had this issue with the thieves guild, completely missed them out and was wondering why I was missing 10%
That's it. Basically every mission in the DNA menu that has a Sync % next to it.