It’s much better than the first one.
I haven’t finished it, but the story so far seems more… believable. As in, instead of being a shadowy mystical Hashashin who ends up killing both crusaders and Muslims and hearing them make long, long speeches post mortem, you’re a petty Italian nobleman who goes on a killing spree to avenge the death of his father and brothers. Of course, Daddy was an Assassin, and got killed off as a result of some conspiracy, but this being 15th century Italy, conspiracies are par for the course, and there’s little emphasis put so far on pieces of Eden and ancestral plots (and I’m up to the last few kills, I think). The conspiracy also involves actual, historical plots, such as the Pazzi revolt in Florence.
The present timeline is less interesting than it was, since there’s less mystery, but then there’s less of it - instead of going back each time you kill a target, you go back at rare intervals in the story.
As for the gameplay, it hasn’t changed much, except melee combat with lots of guards is more difficult (parrying and countering isn’t the be all, end all anymore, and some types of guards make you pay when you try that little trick), but you have lots more gimmicks up your sleeve to avoid such fights. Some gimmicks make the game very easy indeed (such as smoke bombs), but of course you don’t *have *to use them.
There’s also less mandatory faffing about before you get to kill someone (you know, the eavesdropping, pickpocketing, racing missions of the 1). The missions are still there, but they’re optional and only give you some money to buy gear with, and to have fun. There’s also more variety in them.
Finally, there’s a grand scavenger hunt across the whole game to find and decode information left in the Animus by your predecessor, which has a definite “Da Vinci Code” feel to it, with puzzles hidden in architecture and such. And speaking of architecture, climbing up the Duomo, or the Palazzo of the Doges feels awesome, esp. when you’ve seen them IRL - they’re really close to the real thing.
You still can’t save whenever you want, but there are more checkpoints during missions, so if you fail at one point, you respawn mid-mission rather than at the Assassin Bureau across the city.
There’re two annoyances with the gameplay though : your villa, and notoriety. Your villa is how you make money and buy equipment, only it’s in ruins, so you must invest in it. After you’ve done so a little bit, it starts producing money every 20 minutes, but it can only hold so much money total, meaning you’ve got to come back to it every now and then to empty the chests and invest some more. Thanks to instant travel, it’s pretty quick, but it’s still a bit of a bore.
Notoriety is the system put in place that makes guards more or less aware of you. If you do weird things in public, or pickpocket too many civilians, your notoriety goes up, and more guards are suspicious of you in the streets. To make it go down, you have to find wanted posters of you, or bribe town criers. Since most missions raise your notoriety, you spend much time doing so - but again, you don’t have to if you don’t care to. It just makes the game more difficult if you don’t.
Finally, the controls haven’t changed much at all.