Some people can't understand the appeal of running. Despite what enthusiasts may tell them, they'll always see it as a hideous form of exercise, a strenuous and tedious undertaking that leaves you in a panting, sweaty heap. At the same time, there are also people who are baffled by the popularity of video games. Why, they wonder, would anyone want to spend an entire day cramped up inside, hammering on a plastic joypad? Do they not feel the need to go outside, to get their heart pumping and to feel the sun on their face?

Assassins Creed 2 understands both these pleasures. It is a game that celebrates the joy of physical activity, of running and jumping and climbing to the top of the highest building. At the same time, it also knows that video games primarily exist to give us experiences that we could not access in real life. Very few of us could scale the side of a castle with our bare hands; even fewer of us would then be able to murder a prominent Italian merchant and his guards using our incredible hand-to-hand combat skills.

Enough preamble. My point is that AC2 is one of those games that revels in escapism, offering us massive playgrounds to fool about in. I'm increasingly forming the opinion that the Creed series is this generation's Tomb Raider, in the sense that its huge levels immediately create an irresistible urge to go off and explore. As before, you can climb to the top of pretty much any structure you can see. Our new assassin, Ezio, is a brilliantly nimble hero, and it's so easy to move him around that there's plenty of fun to be had in ignoring your objectives and just going on the prowl, toying around with the many mechanics on offer. Of course, this was equally true of the last game. From what we've seen so far, it seems that much of the core gameplay will be very similar to the first Assassin's Creed, but Ezio's new abilities certainly bring new options to the table - and as the screenshots show, the level of graphical detail is nothing short of incredible.

Ubisoft's latest demo, now showing at the Tokyo Games Show, finds Ezio prowling the busy streets of Renaissance-era Venice. The mission on display is familiar in its structure: Ezio starts by climbing to the top of the highest building in the city so that he can "synchronise" with his surroundings - the process that reveals important data on the map and radar. Like the first game, the concept here is that we're playing through a memory of Ezio's activities as they are recalled by his present-day ancestor, a chap named Desmond. Once the syncing is complete the player heads off to meet an ally, Antonio, who then gives us some important information about the target - a villainous merchant named Emilio. It turns out that this victim-to-be is being protected by five archers who are hanging around the city's rooftops, so Ezio has to take out these watchdogs before he can progress. Once the archers are dead, Antonio's henchmen will steal their clothes and take their place - allowing Ezio to proceed to the target. Once you're inside Emilio's courtyard, you'll have a limited amount of time to find and kill him- either by sneaking up on him, or by battling your way through his bodyguards.

Naturally, you're given quite a bit of freedom in terms of how you approach these goals. Clearly you'll have to climb up high to get at the archers, but it's up to you whether you want to be stealthy and sneak up on the Robin Hood-wannabes, or whether you'd rather dash straight at them like a psychopathic parkour expert. Ezio is a remarkably versatile killer, so either approach will work. If you can get yourself into a position directly above a guard, you can easily drop down and execute them with an efficient stab - and in fact Ezio is so good that he can wipe out two opponents at once in this manner. On the other hand, there are wealth of options should you find yourself in direct combat. You can strafe, counter, or dodge incoming blows - and if you're fighting bare-handed, you can easily snatch a weapon from your enemy's grasp. Grabbing an enemy allows you to head butt them, to hurl them over the nearest rooftop or, best of all, to steer them into the path of enemy attacks. At one point in the demo, I swung an archer around so that he was punctured by an incoming arrow from one of his mates - a hugely satisfying way to dispose of an enemy.

Have a nice trip....

There are dozens of nice touches that help to make combat a gratifying experience. Arrows that find their mark will visibly protrude from their target; guards swear in Italian as they circle and swipe at you, while melee combat is pleasingly heavy and solid in its sound and animation. But there's a similar level of detail in your more subtle actions, too. AC1's Altair had the ability to hide within groups of scholars, but Ezio can blend into any group of people that are heading in the same direction - just move slowly within the gaggle of bodies, and his outline will turn white, indicate his near-invisibility.

If you need to get past a particular foe and you don't want to kill him, you might need a bit of hired help. For a small fee, Ezio can hire a band of courtesans to accompany him around the city. While he's surrounded by these beautiful ladies, our hero is once again hidden from suspicious eyes. When you need a distraction, you can then send in the gals to flirt with a specific guard - an action that triggers some brilliantly expressive reactions from your target. Alternatively, you might want to hire a gang of thieves to lend a hand. These dastardly blaggards can fight alongside you, or cause a ruckus by robbing nearby civilians, drawing the attention of the local authorities.

As it happens, you might want to do a bit of thieving yourself - because it seems that money will play a fairly significant role in Assassins Creed 2. In addition to upgrading your weapons and equipment, you'll be able to use your funds to customise Ezio's villa, which you can visit between missions. I've not seen anything of this yet, but apparently this location will act as a kind of interactive trophy room. You'll be able to inspect items retrieved from your victims, and furthermore you'll be able to purchase decorative works of art - including digitised versions of real, renaissance-era artworks. If you've ever wanted to own an original painting by Botticelli, now's your chance.

There will be 130 missions in the full game, including a hefty dose of side quests, divided across 15 different types of assignment. Ubisoft is well aware that a lack of variety was one of the biggest criticisms last time around, but this time it's promised to keep things changeable. You'll also be able to revisit missions at any time you like by accessing a bank of Ezio's memories, and there's also a sort of in-game encyclopedia that offers detailed information on gameplay mechanics and the places you visit.

Above all else, however, I'm looking forward to just fooling around in 15th Century Italy. Towards the end of my hands-on with the game, I murdered a guard and dumped his body over the edge of a roof. The civilians on the ground below started to panic, so I whipped out my wallet and started throwing money down onto the body. People started rushing to pick up the coins I'd dropped, and were so distracted that they failed to notice when I dropped down and started pick pocketing everyone in sight. Eventually, about five people realised they had been robbed at exactly the same time, leading to a chase in which I was pursued by half of Venice. If messing about for five minutes can yield that much chaos, I can't wait to find out what can be done in the full game.

Assassins Creed 2 will be released on PS3 and Xbox 360 on November 20, with the PC version to follow in 2010.