By The Book
Ultra rare0.1%All-the-thingsOptionalSingle-player
Complete 100% of all main mission constraints.
100% of every main mission's optional constraints - the full-sync objectives (kill a certain way, don't take damage, finish under time, etc.) across all memory sequences. Replay any memory from the DNA menu to nail the ones you missed, so it's tedious rather than missable. The single biggest step toward 100%.