Assassin's Creed may well have been a resounding success for game developer Ubisoft (it has sold more than 9 million copies since its launch two years ago) but the game's creative director, Patrice Desilets, admits the first thing he and his team did before starting work on the sequel was listen to fan feedback, including the main complaints.

"In the first game, I think we made a bit of a mistake of showing the game structure too much and not changing it throughout the game experience, which became a little repetitive," Mr Desilets says.

"So this time around it's clear that the story is to be much more important than the game structure, making it more organic."

Like the prequel, Assassin's Creed 2 centres on the exploits of a stealth assassin and while the overarching storyline is a continuation of the first game, this sequel's time period, locations and cast of characters are all different.

Rather than focusing on a trained killer from the start, the plot follows Ezio as a young nobleman-turned-assassin who wants retribution for the murder of his family.

It's this empathy, along with the game's refined learning curve, that Mr Desilets believes will create a more powerful link between Ezio and players. "We made sure a lot of the frustrations of the first game are gone, too," he says. "If you are frustrated about your main character, that personal link is tougher to make."

Set in Renaissance Italy, the game gives players the freedom to roam through stunningly remodelled cities Venice, Rome and Florence, plus there are new puzzle-oriented catacombs to explore. As well as Ezio's new ability to swim, he also moves around by gondola and a flying machine developed by Leonardo da Vinci. Mr Desilets says the storyline teams Ezio and da Vinci as best friends. "In the story, you'll see a really nice relationship between them, plus young Leo is a bit like James Bond's Q, in that he invents things to assist Ezio."

The sequel features a new currency system that presents players with the traditional options to buy weapons and customise the look of Ezio.

"I asked the team to make sure, though, that we really use the money option in different situations, not just to buy weapons," Mr Desilets says. "So you can use it to bribe others, hire mercenaries, even just throw money on the ground to attract people as a decoy."

As well as the freedom to perform the main story-driven missions at your own pace, there is an equal portion of optional side-quests to play that don't all involve being an assassin, such as gathering information and being a courier.

"We expect the game to take roughly 20 to 25 hours to complete at a normal pace as you discover the world but there is so much stuff around it that it will likely take much longer than that," Mr Desilets says.

As to whether players are in for another plot-twisting climax, he says: "It's going to be just like the first game, in that it will leave the best surprise till last."

By MIKE WILCOX