Complete DNA Sequence 1.

Enter the Animus 2.0.

Be reborn as Ezio Auditore Da Firenze.

Accept a new job from Morrison after the Red Grave incident. (Dante only)

Clear Mission 17 as Nero, Dante, or V.

Rack up a total of 60 minutes in the air by jumping or other means

Clear Mission 12 as Nero, Dante, or V.

Unlocked the Secret Exit in Unbearable.

Don't feel guilty about jumping on him.

Complete Vergil's downfall

Defeat an Imprisoner

Use proper timing to get a leg up in battle against the boss in Mission 11 as Nero, Dante, or V.

Destroy a certain wall in Mission 09 as Nero, Dante, or V.