7 years too late, but here I am!
The game is set in two different eras: Present day, with Desmond Miles, and during the Third Crusade as Desmond's ancestor Altair. Desmond is captured, before the game's beginning, by Abstergo and is now strapped to the Animus, a machine that puts him in the place of his ancestors, in this case, Altair. Turns out Desmond is a descendant from a long line of Assassins, and by relieving Altair's crusade against the Templars, Abstergo aims to obtain something. Desmond's short sequences are easily the most boring, but they are a bit interesting, Altair's story is much more interesting. The story itself is alright, and while the dialogue is nothing special, it does have a couple of shining lines. Furthermore, the whole lore surrounding the Assassins and Templars is very interesting. Oh, and the game ends with one of the biggest cliff hangers ever conceived, not cool Ubisoft!
Combat is fairly simple, and Altair packs a couple of weapons to make his job easier. The Hidden Blade is useless in battle, but it can be used to kill unsuspecting or fallen enemies, but when it comes to fighting he wields a sword and a small knife. The knife doubles as the projectile weapon, according to the distance, Altair will shoot a knife or try to hit his enemies with it. Fighting with the sword or the knife, at close quarters, is virtually the same, you can mash on the attack button to attack, time a Counter Attack(Which may or may not kill, which means its usefulness can vary!) or sidestep. To be honest, combat is dead simple and easy, only a couple of enemies can perform counterattacks and most of the time mashing on the attack button is all you really need.
The game also offers some optional quests in the form of hidden flags throughout the towns and 60 hidden Templars for Altair to defeat, but since the PS3 version has no trophies, they are not worth it. One thing that really irked me is that you can't manually save the game, you must rely on the autosave system. The game autosaves every time you find a collectible or clear a side quest, but it would've been nice to be able to save at will. Another annoyance, albeit much minor, is that when you are selecting a Memory Section, the nice Abstergo scientist will nag on Desmond, it quickly grows annoying when you are just checking stuff out.
Assassin's Creed was a very decent first game, but it clearly needed a lot of polishing, and as repetitive as it got, I found myself having more fun than I expected.
6.5 out of 10.