First up the graphics are incredible! There are way more NPC's on the screen than what the PS3 could handle. Game play wise they have made a lot of changes, a lot of good and a few bad. Free running is a lot better hold R1+X (RB+A) to run up and R1+O (RB+B) to run down. Both profiles change to way you move and the way you move is not a lot more fluid with a lot more tricks to preform.
In Unitiy you don't leave the animus, however you do have two aspect's played in the present. You play as yourself, and are contacted in a way that would spoil things for you if I say any more. Secondly there are other real people out there that you can help in game and not all of them are in the same time period. Can't say anything more than that or it'll be spoiled for you.
The first negative point is that there is no naval combat. To me this makes no sense as there were many many naval battles between England and France. Have Ubisoft never heard of the Battle of Trafalgar?
Next up is the close in battle camera, this is both cool and annoying. One on one battles are awesome like this, but sometimes another enemy enters the fray and he attacks before you can actually see him.
I can't figure out why they have put a cool down timer on Eagle Vision. It doesn't make sense as the other games have made in infinite in the past. An odd de-evolution.
Back to cool: While I am yet to try many of its features Co-op is very new and from what I have seen could be very exciting! Clubs are in-game guilds built for the new Co-op system and you can create an explore-able clubhouse in East Paris.
Ok a problem with the story: Where is Marrie Antoinette? In 1789, Marrie Antoinette was told that her French subjects had no bread she joked the infamous line "Qu'ils mangent de la brioche" or "let the eat cake." This was a pivotal moment that brought about the revolution. Another thing about the game is that I never felt a part of the revolution. I could never tell if we were on the side of the King or the Republicans???
Other than this the game is fantastic. I just wish that I was more involved in the revolution.
Minor spoilers for history buffs like me:
I hope they show us a lot more with DLC as the characters that we do meet in the story that I longed to see brought to life I was expecting to get into serious trouble with the Marquis de Sade (if you don't know about him look him up or watch the film by Jeffery Rush), or causing trouble for the English with Napoleon, the problem is is that they got only a fraction of screen time and I found that to be disappointing.