This cannot be achieved in Sequence 1.
To achieve 100% Synchronization for a Memory, you must complete a secondary objective for that memory. These secondary objectives can range from completing the memory within a set time, complete the memory without getting detected or playing through the memory a certain way. Once 100% Synchronization has been completed on a certain memory, it is complete and does not need to be replayed. You can replay any memory that you have not completed to 100%.
The easiest Sequence to complete is DNA Sequence 3; "The Fighter, The Lover and The Thief." The following is the second objectives for each memory. Complete each secondary objective, and you'll earn 100% synchronization for each memory. After you've earned 100% for each memory, the achievement will unlock.
- Sequence 3-Memory 1: Do not be detected while reducing Notoriety. Remain undetected until rejoining La Volpe at the Thieves Guild.
- Sequence 3-Memory 2: Kill only the Borgia Captain.
- Sequence 3-Memory 3: Do not Swim.
- Sequence 3-Memory 4: None