Assassin's Creed II Cheats

Messer Sandman (10): Stun 4 guards at once by throwing sand in their face.
Doctor (20): Perform an Air Assassination on a Poisoned NPC.
No-hitter (20): Kill 10 enemies while remaining in conflict without being hit.
Kleptomaniac (10): Pickpocket 1000 Florins.
Lightning Strike (10): Sprint for 100 meters.
Sweeper (10): Sweep 5 guards at once by using a Long Weapon.
Venetian Gladiator (20): Discover the Assassin’s Tomb inside Santa Maria della Visitazione.
I can see your house from here! (20): Discover the Assassin’s Tomb inside the Torre Grossa.
Hallowed be thy name (20): Discover the Assassin’s Tomb inside the Basilica di San Marco.
Prison Escape (20): Discover the Assassin’s Tomb inside the Rocca di Ravaldino fortress.
Choir Boy (20) (The Duomo): Discover the Assassin’s Tomb inside Santa Maria del Fiore .
Assassin For Hire (10): Complete your first assassination mission for Lorenzo Il Magnifico.
Macho Man (10): Defend a woman’s honor.
Steal Home: Win a race against thieves! 10) Show your Colors (10): Wear the Auditore cape in each city.
Handy Man (10): Upgrade a building in the Stronghold.
I like the view (10): Synchronize 10 View Points.
High Dive (10): Perform a Leap of Faith from the Top of Florence’s Giotto’s Campanile.
Mailman (10): Intercept a Borgia Courrier.
Tip of the Iceberg (10): Use your Eagle Vision to scan a Glyph in the environment.
A Piece of the Puzzle (10): Unlock a piece of Subject 16’s video.
Art Connoisseur (10): Buy a Painting from Florence and Venice.
Podestà of Monteriggioni (30): Reach 80% of your stronghold’s total value.
Perfect Harmony (10): Tint your clothes with those colors: Wetland Ebony and Wetland Ivory.
In Memory of Petruccio (30): Collect all the Feathers.
Red Light Addict (10): Spend 5000 florins on Courtesans.
Man of the People (10): Toss more than 300 florins on the ground.
Victory lies in preparation (10): Get all Hidden Blades, Item Pouches and Armor upgrades for Ezio.

Collecting Feathers
Just collect feathers within the game to unlock the items following. After collecting the amount needed to unlock an item just put it in the box in your villa and talk to your mother.

Auditore Cape: Collect 100 feathers
Condottiero War Hammer: Collect 50 feathers

Run through the air (Pre-Patch)
Equip the throwing knives and hold down RT + X while running off any roof. Ezio will continue running in a straight line off the roof in the air. When you want to get down release the buttons or switch to another weapon. If you drop down you won't throw the knife but if you rech another roof you will waste ammo so switch to another weapon instead to conserve your knives.