Lower Notoriety
Completing various high-profile assassinations will undoubtedly raise Ezio's Notoriety level in Italy. There is a way to rapidly lower Ezio's Notoriety before he becomes "Notorious." Visit a Herald and bribe him to lower the Notoriety level significantly. After bribing the Herald, players can simply steal their money back.
Unlock Items With Feathers
Collecting feathers is one of the game's side quests. The feathers are placed along the main areas of Italy where all of the missions occur. Climb to rooftops and use your Eagle Vision special ability to find feathers (which have a silver glow to them). The final few feathers can be found by pausing the game and accessing the DNA strand. The end of the strand shows where the feathers are located in Italy. Collect 50 feathers to unlock the "Condottiero War Hammer," a powerful weapon. To unlock the "Auditore Cape," collect 100 feathers. After collecting enough feathers, place them in the box in Ezio's villa and talk to the character's mother.
Unlock Special Abilities
Ezio can become a more powerful assassin after receiving a few special abilities. Successfully complete Rosa's "Monkey See, Monkey Do" mission from Sequence 7. The "Climb Leap" ability will be unlocked for in-game use. This ability allows Ezio to jump higher while climbing, thus opening up new areas of Italy to explore. The "Disarm" special ability is unlocked after completing the "Evasive Maneuvers" mission from Sequence 5. This ability allows players to counterattacks from heavier weapons, such as axes and swords.
Super Mario Easter Egg
"Assassin's Creed 2" also includes a reference to Nintendo's Super Mario series. At the beginning of Sequence 3, Ezio has to escort Maria and Claudia to the village. The trio is approached by a group of villains. Fortunately, Ezio's uncle appears and saves the group from the villains. Walk up to Ezio's uncle and talk to him. In a nod to Super Mario the uncle will say, "Don't you recognize me? Its-a me, Mario!"