Assassin's Creed features one of the most unique gameworlds ever created: beautiful, memorable, and alive. Every crack and crevasse is filled with gorgeous, subtle details, from astounding visual flourishes to overheard cries for help. But it's more than just a world--it's a fun and exciting action game with a ton of stuff to do and places to explore, rounded out with a complex story that will slowly grab you the more you play. The PC version has a few more issues than its console counterparts, and the keyboard-and-mouse controls strip away some of the smooth magic of exploration. Nevertheless, if you don't mind plugging in a gamepad and have a system that exceeds the system requirements, you'll find the same free-form travels and atmospheric game world that console owners enjoyed last year.

Cities are alive with activity.

Not enough can be said about the living, breathing universe that you'll inhabit in Assassin's Creed. As assassin extraordinaire Altair, you'll explore three major cities of the Holy Land in the 12th century: Jerusalem, Damascus, and Acre. Each city is beautifully rendered from top to bottom and features meticulously crafted towers that reach for the sky, bustling market squares, and quiet corners where citizens converse and drunks lie in wait to accost you. As you wander the streets (and rooftops), you'll push your way through crowds of women carrying jars on their heads, hear orators shout political and religious wisdom, and watch town guards harass innocent victims. Altair has a profound effect on this world, but the cities are entities all their own, with their own flows and personalities.

The visual design has a lot to do with how believably organic everything feels. The cities are absolutely huge, and though you don't get full exploration privileges in the first few chapters, they eventually open up to let you travel seamlessly from one side to another. Everything is beautifully lit with just the right amount of bloom effect, and almost everything casts a shadow, from tall pillars to Altair's cloak. In fact, sometimes the shadows get to be a bit much and may make you think for a moment that there is artifacting on your screen, when in fact it's a character's head casting a shadow on his or her own neck. Every object, from scaffolds to pottery, is textured so finely that you'll feel as if you could reach out and touch it. Animations are almost as equally well done. Altair scales walls, leaps majestically from towers, and engages in swashbuckling swordfights that would make Errol Flynn proud. And he does it all with fluid ease, generally moving from one pose to another without a hitch. Minor characters move with less aplomb, but that's easy to forgive, considering that the cities are populated with thousands and thousands of individuals.

On a high-powered PC, these elements look even more stunning than they did on the Xbox 360 and PlayStation 3, but the splendor comes with a price: The minimum requirements to play Assassin's Creed are surprisingly high, particularly where the CPU is concerned (a dual-core processor is mandatory). On one test PC that runs Crysis at a respectable frame rate on medium settings, Assassin's Creed slowed to a crawl at lower settings. A high-end test machine ran the game with much better results, though with some occasional slowdown.

What you hear is even more impressive than what you see. At the top of a temple, you hear little but the rush of wind, the twittering of birds, and the barking of a far-off dog. In the most populated areas, your ears will fill with the din of street vendors, the pleas of beggars, and the occasional humming. It's never too much, though, and the game does a good job of making sure you hear what you need to hear (for example, the cries of citizens who need your help) without filling your ears with pointless noise. The voice acting of the supporting cast is similarly remarkable. Conversations are completely believable and delivered with the perfect amount of solemn dignity. Oddly, the weakest link is Altair himself. Actor Philip Shahbaz does an all right job, but he isn't up to par with the first-rate acting of his fellow troupe. Rounding it all out is a beautiful orchestral score that is most notable for its subtlety. Many of the game's most impressive moments are accompanied by lovely musical themes that add even more threads to the game's rich living tapestry. We did run into some audio glitches on two of our three test systems, however, in which sound effects would occasionally stutter and hitch. The game's readme file included a potential workaround for this issue, though in our case, it didn't solve it.

The combat is simple but surprisingly engaging.

The story that binds it all together rises to the occasion. Actually, there are two related stories in play. The unfolding drama of Crusades-era Palestine is a mere memory, forcibly pulled from a modern-day bartender named Desmond by a resolute researcher using a machine called an animus. The memories aren't Desmond's own--they are Altair's, stored safely in the hapless subject's genetic code. We follow Altair as he assassinates nine public figures at the command of his master, and as the common thread that ties these men comes into focus, so does the true identity of Desmond's captors. There are no cutscenes in the traditional sense; every bit of story exposition and dialogue flows smoothly from the gameplay and takes place entirely within the game engine. The ending is confusing and blatantly leaves open the possibility of a sequel, but this is a small blemish on an otherwise stirring tale. Altair's world is not one of absolutes. His assassination targets aren't always evil, and Altair isn't always likable. As he is fond of reminding us, "Nothing is true. Everything is permitted."

Of course, such an authentic world would be meaningless without a lot of fun things to do in it. Thankfully, Assassin's Creed is endlessly entertaining in that it features a fine mix of stealthy exploration, tight platforming, and exciting combat. To discover the whereabouts of your assassination targets, you must first follow up on possible leads. There are several different mission types in this regard. In some cases, you sit on a bench and listen in on secret conversations. At other times, you will closely follow someone carrying an important letter that you'll pickpocket. Alternately, you can beat the information out of your target. There are also some tasks specific to this version of the game. Oddly, some of these new missions feel more contrived than the others, such as timed sprints and escort tasks in which guards execute scripted attacks as you move to your destination. Since the game's greatest strengths lie in its unscripted events, these additional tasks feel less organic than the others. On the other hand, missions that let you silently assassinate rooftop archers and fling guards into market stands are more interesting and fit better into the game's sandbox world.

There are also some optional missions, such as rescuing innocent townspeople from the clutches of guards. The reward for doing so is a group of vigilantes who will hang out in the area afterward and hinder any foes chasing you. It's also a good way to try out Assassin's Creed's combat, which is surprisingly satisfying, considering the game's focus on sneaking around. You can pounce on enemies using your hidden blade (an incredibly rewarding one-stab kill), or use throwing daggers to take enemies down from a distance. However, your sword is your melee mainstay, and though the hack-and-slash combat may seem simple at first, it gets more challenging once you unlock the various countermoves. Often, you'll have a dozen or more attackers to fend off at once, but though these fights can be a little tricky, you'll never feel as if you're in over your head. In fact, the few circumstances in which you are forced into combat--such as a late-game boss fight against a seemingly endless crowd of attackers and their leering leader--are challenging and require some pitch-perfect timing to counter every strike and lunge.

It isn't what it looks like...

Nevertheless, brute force is rarely the best way to handle a situation. You want to slink unnoticed through the crowds, but you can draw attention to yourself in a number of ways--whether it's galloping past a guard station on a horse, knocking pottery off of someone's head, or getting so frustrated by the various beggars that you fling them away from you. (And trust us--these are the most aggressive panhandlers you'll ever meet.) If you antagonize the guards, they'll give chase. Yes, you can stick around and fight, and though it's never the easiest option, breaking stealth does not damn you to death like it does in other sneaking games. But why not lure them to a rooftop? Once up there, you can grab them and fling them to the street below. Or if there are too many of them, you can jump across the rooftops gracefully until you find a hiding place, such as a nice bale of hay or a curtained garden. Once you're hidden, they'll give up the chase and you'll be free to roam about again.

You can also seek refuge in small groups of scholars who serve as mobile hiding places. It's a bit contrived to walk into a stationary cluster of scholars and have them suddenly start moving simply because you're there, but it gets the job done. Actually, if there's any drawback to the usually excellent gameplay, it's how synthetic certain elements feel. Vigilantes are always in the same spot, missions reset if you don't get them right the first time, and those same guards will harass that citizen an hour after you pass by. It's easy to forgive these quirks, though, given the easygoing flow of the world surrounding these pockets of gameplay.

Climbing up buildings and jumping around the rooftops is fun and breezy, though keyboard jockeys should be warned that the mouse and keyboard don't deliver the best way to experience the game's fluidity. With a controller, the face buttons are mapped to correspond with Altair's head, hands, and legs; with a keyboard and mouse, the wonder of that arrangement is lost. It's also a bit tougher to time counterattacks using the mouse buttons, though players without controllers needn't worry too much: It's still a relatively comfortable setup. Of course, you can attach a controller, and we were able to use two different gamepads, including an Xbox 360 controller, with success.

Regardless of your preferred scheme, you can leap across alleys and scale walls with ease, and though it's possible to launch yourself from a wall or hurtle through a vendor's booth by accident, these moments aren't very common. You'd think that a city specifically designed to let you climb structures and caper about the roofs would look overly artificial, yet there's never a moment when you will think to yourself, "Wow, that looks like a place where I'm supposed to jump." The architecture looks completely natural, which makes Altair's abilities all the more exciting to pull off. The environments don't look as if they were created for him to climb around on; he just uses the hand he's been dealt, as any good assassin should.

Sometimes, you'll literally pray you don't get caught by vigilant guards.

In Assassin's Creed, the greatest joy comes from the smallest details, and for every nerve-racking battle, there's a quiet moment that cuts to the game's heart and soul. Climbing towers to uncover portions of the map is a simple mechanic but forever satisfying, thanks to the beautiful vistas and soft musical themes that accompany the view. Even the beggars that pester you are amusing and fun, though their constant shoving can be annoying when you're trying to pickpocket a pedestrian or eliminate a target without a fuss. It all makes your missions that much more compelling, and you'll be inclined to explore every nook and cranny and take on every optional task just for the fun of it. There's a ton of stuff to do, and even when you've exhausted your official tasks, you can search for the collectible flags and crosses strewn around the cities and countryside. You could probably plow through the main quest in 20 hours or less, but completists might spend many more finishing every quest and gathering every flag.

The PC version of Assassin's Creed isn't the superior one, but this is a case where translation to the PC resulted in some minor hiccups rather than obvious gaffes. If you don't have the opportunity to play it on the Xbox 360 or PlayStation 3, you should pick up a copy and immerse yourself in its memorable world. It's the kind of game you want to show your friends even if they're not into games, and if you have a high-powered computer, it's one that should be in your collection.

• Huge, gorgeous world that feels wholly alive  
• It's fun to run across city rooftops  
• Joyous mix of stealth, action, and platforming  
• Stunning sound design features fantastic voice acting and a beautiful musical score  
• Tons of small details will constantly amaze you.