Two words can describe Assassins Creed; interactive and splendid. Thats not to say it is perfect, there are some flaws.
Once inside the actual memory of the cool guy and the cool story, you get a real tasty treat. Many complain that the game play is repetitive, but it actually isn't. You choose which way you want to go and how you want to accomplish a task, using the game play your given. You make the game as fun as your willing to make it.
I personally took great joy in the aspect of stealth assassinating folks, and then running around the cities like spider man without webs was amazing.
In fact, if there is something to compare this game to is the spider man games with the free roaming cities. Except Assassins Creed has more detailed environments and actions with said environments. You explore at will accepting missions as you please and beating up some baddies (or goodies, hehehe) as you wish.
The main assassinations are great, after completing 3 side quests to gather "intelligence" on your prey you begin the trek into their domain where you proceed to either kill them, fight some guys or start chasing them. The only problem is the cut scene after you stab them in the neck, they talk for about 4-5 minutes each. After being stabbed in the neck I'd be silent, but this is the crusades so obviously everyone is more powerful then we are.
Using the hidden blade while snooping around on ground and the throwing knives while snooping around on roofs is delightful. Then comes the sword combat.
The sword combat is not bad, but I think it could use some tweaks here and there. At first you don't have the counter attack (which is vital to use) so it sucks, but then with the counter attack you can stab, slice and impale your way through one guard at a time. The counter attacks are very cinematic and cool, its just pulling them off is an annoyance as well as the other moves available.
There are these moments when your not even playing as Altaire, and it is just an excuse for nothing. These gaps in game play are actually pointless. Its just the hostage constantly saying "tell me something" and "why am I here" and they keep saying "...." nothing. They say nothing important and leave you in the shadows and you feel like you literally are wasting your life.
The sound effects and music are fantastic, but the voice acting is average if not below average. They explain why everyone is speaking English, but it has to do with the terrible sci-fi portion of the game.
In the end this game is exceptional. It brings new game play and aspects as well as fun game play. A lacking plot and mild blips in sword combat are not enough to turn gamers away, you must try it.