Playing the new Xbox 360 demo for Assassin's Creed at this year's E3, I finally got a feel for what makes the game so mesmerizing: its beautiful fluidity. The effortless flow of the protagonist's movements permeate the gameplay as he essentially swims through a sea of bodies and buildings. Just running on rooftops and climbing on walls without having a mission is a great deal of fun, which says lots about the game's playability. This element actually reminded me of Real Time Worlds' Crackdown in an exploratory sense, though jumping through the cities in that game lacked the elegance of Assassin's hero.

Unfortunately, Ubisoft's skilled implementation of a nearly liquid environment plays so amazingly that less polished gameplay elements like sword combat noticeably break the game's flow. When leaping between balconies and rooftops, slinking stealthily through crowds and silently assassinating evil fucks, you do not at all need the change of pace brought on by having a slow-paced standoff against four enemies with swords.

As protagonist assassin Altair, I began the demo mission atop a church in the center of 12th century Jerusalem. A fairly impressive draw distance gives a view of much of the surrounding area, even outside the walls of the city--an Ubisoft rep said the demo map this year is 15 times bigger than last year's. Still, up close, building textures weren't exactly stunning, with muddled graphics detracting from most of the city's stone structures. The player would normally have to obtain mission details before being sent on the prowl, but the demo allowed me to skip those elements and hit the ground running. I already knew I was after a slave trader named Talal, who was pinpointed on my minimap. All I needed to do was find him and put him to rest.

Making my way unobtrusively through the crowds on the city streets, I reached one of those points where developers herald the "open-endedness" and "replayability" of a situation. There were some guards around whom I needed to sneak. As in many games, there are supposedly some great number of options, but in reality there are three practical choices, two of which were markedly interesting.

I had already seen one way to get past the sentries at last year's E3 demo--assume a pious position and blend in with the white-garbed monks as they make their way down the road. An Ubisoft rep had demonstrated a second way to get through using an obviously precariously positioned guard atop a nearby building. Shove. Alarm. Confusion. Success. I chose a third and far less dramatic path by jumping roofs to the opposite side of the city and approaching my victim's location from behind.

Having lots of choices in a game like Assassin's Creed is by no means a bad thing, but it tends to be the case that the few options actually scripted by the developers to be interesting are the most rewarding.

Before I could kill the slave-trading evildoer, I had to deal with several of his cronies in his lair. Again, the battle did not have the same smoothness of the rest of the gameplay. With multiple sword-wielders around me, the best strategy seemed to be to wait for my enemies to attack and then to counter their assaults, taking them out one by one. There did not seem to be an effective way to chain attacks together to match the fluidity of Altair's acrobatics. Even finishing off fallen foes required manually switching from a sword to stealth dagger.

Like any cowardly slave monger, Talal fled after I crushed his footsoldiers, prompting a chase sequence--a perfect showcase for Altair's agility. I tailed Talal through the city's upper levels, tracking him as he ran through the streets and alleyways down below. The resulting public assassination required me to flee to a hidden bungalow on the rooftops to let things calm down before returning to the assassin's base. In both the chase and the flight sequences, I could feel the tangible high tension of the moment. I loved it.

Even with the fairly weak fighting sequences, the sheer freedom provided by Altair’s movements and the sprawling cityscapes make Assassin's Creed an incredible achievement--after all, you can grab onto any ledge that is at least two inches thick. Going from walking in "low profile" mode to the running and climbing "high profile" mode is as easy as holding down the right trigger. The game has the makings of a brilliant experience in its current form. With a few changes, it could be my new favorite drug. My current favorite is meth.

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