A solid experience that plays it a bit safe.
More than though are the tweaks, most of which are resounding successes. For instance, the addition of the crossbow is about as handy and awesome as it sounds. Long-range stealth weapon opens up so many possibilities and it's just a damned satisfying weapon to use.
I also found the combat system had been tweaked a little. You'll find yourself actually attacking a lot more, instead of relying 90% on counter-kills. Dodges feel more needed than in the last game and the addition of a kick to break opponents guards means that attacking can be as effective as the old counter-kill. The kick mechanic means that offence can actually be an advisable strategy in Brotherhood's combat portions, which is fresh.
There are other cool little additions as well: a parachute, poison darts, using your pistol in hand to hand combat, two-handed weapons that can be held onto, etc. All of these things are completely optional on the part of the player, but all work perfectly fine and add fun little touches as a whole.
The best thing about Brotherhood however is just how much game there is here. There's a lot of content and truly, it's one of those sandbox games where it just feels like there's so much to do at any given time. You'll often find yourself spending huge amounts of time between actual story missions. There are Followers of Romulus lairs to explore (basically, advanced platforming stages much like the sanctuaries last game), each of which offers a unique experience and atmosphere. There are Borgia towers to burnt. There are Guild Challenges. There's lots to occupy you.
Another of these things to pass the time with is the new renovation mechanic. In Brotherhood, you no longer do all your renovations in one place; rather, you approach what you want to renovate and do so. Similarly, you can collect money from any bank in the city, which saves a ton of time and really convenient. This also means that you'll have a lot more renovating to do, greatly expanding on that experience from the last game.
What's Not-so-Good: Thankfully, due to the amount of content here and a surprisingly length campaign and story, Brotherhood avoids the obvious pitfall of feeling like a full-priced expansion pack.
That being said, it's hard not to notice a lack of ambition here when compared to the last game. There's lots of fun little tweaks and additions, but outside of the multiplayer, there isn't much that's truly groundbreaking.
Perhaps most disappointing on this front is the fact that the entire game is confined to Rome. Given the full length campaign, this ends up making the surroundings feel a little drab and even monotonous compared to the last game. It's also the one thing that makes the game head a bit into expansion pack territory. Keeping it all in one city feels like an obvious bit of self-restraint on the part of the developers, and it also stops the game from feeling as grandiose an experience as AC2.
It's also worth mentioning that, however big Rome is, this also makes horse-riding a very minute part of the game, especially compared to the previous two Assassin's Creed games. You'll probably find yourself doing very little riding at all.
Then there's the story. It's not bad, but certainly not as compelling as the previous game's. Ezio is still a great character and his supporting cast (Claudia, Bart, Volpe, Machiavelli) are all solid. It's just that the actual story is fairly unambitious in concept and lacking in any twists, surprises, or anything truly compelling. It's a fairly basic story with your favourite characters, basically.
Then, we get the ending, which in typical Assassin's Creed fashion, is a bit of a mess. It's difficult to understand, it's a cliffhanger (again), and...well...the transition between the Ezio portion and the Desmond level at the end feels weird, as though we're playing two different games. It's even more of a disjunction than the last level was in the last game. The present-day sci-fi stuff still doesn't meld all that well with the historical portions.
Conclusion: Despite my griping, this is still a fairly solid experience. It's much less ambitious than AC 2 was, but I'd still recommend getting this regardless.
Grade: 8.5/10