From the official Assassin's Creed forums:
"Sooo I'm looking at the new Game Informer right now, and it tells a few thing but only has one new image, the one we already have, the 5th one.
- You'll have a ton of new weapons to choose from including an axe, a hammer, a mace, a spear, 2 different sword types, a spear axe thing, and 2 smaller blades
- You CAN swim
- Da Vincis workshop is in the game
- Locations include Saint Marks Basilica, The Grand Canal, The Little Canal, and the Rialto bridge.
- The game opens in 1476, Altair is from 1191
- So you do indeed play as a new ancestor of Altair / Desmond
-You will see the countryside of Tuscany
- The "Auditore" family is mentioned
- The main characters name is Ezio Auditore de Firenze
- He is a nobleman of Florence
- Big characters are in the game including Machiavelli, Caterina Sofrza, and Lorenzo de Medici
- YOU DO INDEED FLY AND THERES A PICTURE OF IT.
and thats just what I got from the pictures. I'll let you know more details as I read more.
- Game will feature a new notoriety system that governs how enemy soldiers and people will treat you.
- You can disarm enemies and use their own weapons against them this time.
- each weapon has a special move.
- 16 unique mission types.
- No more ease dropping or pick pocketing missions.
- If you get beat up to much you will need to see a street side doctor to regain ful strength.
- Hidden objects (like flags in the first one) are there to uncover but this time if you track them down you will get in-game bonuses that make it worth your time.
- Items include, flags, statues, and gold coins and more that isnt mentioned.
- New enemy types with unique attitudes and weaknesses are present in the game. Archers are mentioned, as well as elite enemies, dagger wielders, "Brutish" armored troops with heavy armor and 2 handed swords and axes, and an intelligent halberd enemy will probe hiding places with their weapons if they think you're near by.
- While hiding in a hay bail you can assassinate people this time, but it may expose your position.
- You can still climb towers and ride horses
- The Lorendo de Medici assassination is in the game.
- There is now a night and day sequence in the game.
- 240 people are working on this title."