A stealth game set in the time of the Crusades, Assassin's Creed takes the basic concepts of "stealth games" and adds many more realistic and dynamic features to it. The mainly-urban setting of the game forces the player to consider many more variables than in previous stealth-style games.
The player takes the role of Desmond Miles, who himself is taking the role of his ancestor, Altair, an ancient assassin. Reliving the life of his ancestor through the use of a genetic memory machine called the Animus, Desmond's story intertwines with the events that his ancestor lived through. The mysterious group forcing Desmond to use the Animus, as well as details about the characters Desmond and Altair interact with, are fleshed out as the game continues.
Almost the entire game - except for short sessions between Animus uses - is spent as Altair, and thus he is the focal character in the game. Altair is tasked to kill 9 key figures in the Templar and Crusader hierarchy, each in a different part of one of the game's three cities (not including the assassin's stronghold). To achieve this, Altair must gather intelligence by eavesdropping, pickpocketing valuable documents, and getting information from informants. Furthermore, Altair must prepare for the assassination itself; mapping out the city from high points and helping the local populace, who will then return the favor if Altair is being pursued by guards. The cities are vibrant and dynamic, and interaction with its people is a key trait. Activities that will not arouse suspicion, for example, tend to be low-key things like gently moving through a crowd (pushing people softly aside), walking at a normal pace, and using ladders. In contrast, running or sprinting through a crowded marketplace (knocking people and objects aside) and climbing up the sides of buildings using windows and handholds are things that will draw the attention of the guards.
The gameplay handles excellently. Swordfighting is graceful and fluid, and tends to be "realistic" more than "stylized" despite the inclusion of several "finishing move"-type attacks. Altair's weapons include a hidden blade (useful for quiet, non-suspicious attacks), a sword (more damaging, but heavier), a long dagger (quicker and better for counter-attacking), and throwing knives. Altair is graceful and athletic, and can climb almost any building in the game by moving from various handholds. He can also jump from roof to roof and from various other points; the feeling of speed is emphasized especially when Altair stumbles after hitting someone going full speed, or hits the ground and rolls after a jump. Traveling between cities (in the unsettled middle area known as the Kingdom) requires a horse, and horse handling is also done very well.
The graphics are absolutely beautiful. The environments, the characters, the effects, and even the heads up display are all both stylized and realistic. Characters animate and move very naturally, and the cities are expansive and don't seem like the same 10 buildings over and over. The heads up display, especially, is seamlessly integrated into the story; it represents the Animus, which is noted in the manual to be designed to work like a game to better acclimate subjects to it. The game is a cinematic experience most of the way through, and its visuals are of the highest quality.
The sound is not particularly notable, and is possibly the weakest part of the game. Music is rare, only illuminating fight scenes, and is mostly forgettable. Voices tend to be well-done, in terms of accents and voicing, but are repetitive. Mostly, the sound is a side-part of the game, and not as notable as the other parts.
As a whole, this game is fantastic. It's fun, it looks great, and it's got an interesting urban and medieval twist on the usual sneaking missions. It's definitely recommended to most game fans.
Note: We enjoyed this game so thoroughly that one of us went through the entire game to write a full walkthrough, and the other went all the way through to validate it. The graphics are just amazingly realistic in terms of movement and fighting style.