Definately one of the greatest games of 2009!
Gameplay is improved a lot when the assassins' arsenal is increased by that much. For me, the smoke bomb and 'pistol' is by far the most notable and useful additions. What I loved most is Ubisoft's decision to allow players to buy their own weapon making a solid RPG effect. However everything there is to buy will all become yours before you even realise.
I was looking forward to Desmond's story at first since the first game didn't do a good job on Altair. However Ezio's story is amazing, it isn't very complicated however the process is most enjoyable. I guess what amazed me was allowing the players to witness the transition of a delinquent young child to a master assassin. By the end of the game, Ezio is a hero. On the other hand, Desmond's story was quite disappointing; it's another storyline which tries to freak people out with a certain date.
Surprisingly the music from Assassins Creed was beautiful, it was appropriate for each scene and that easily makes the sound of AC 2 a 10.
Generally I hate collecting things scattered in an open world such as the feathers, however collecting feathers in AC 2 was a joy instead of a chore. This just shows that an enticing reward can make a tedious thing fun.
For the people who collect trophies/achievements, AC 2 is probably the easiest game to get your 'platinum' trophy. I don't really collect them however I got mine in roughly 30 hours.
That's about all I've got to say about this impressive sequel, it is no doubt an amazing game however it didn't really leave anything that was memorable and for that I wouldn't put it in my top 10.