Assassin's Creed 2 has received rave reviews for its stunning visuals. (Ubisoft)

Assassin's Creed 2, the game designed by Ubisoft Montreal, has sold more than 1.6 million copies in its first week, beating expectations set by the company and industry analysts.

Sales of the PlayStation 3 and Xbox 360 game were up by almost a third compared with sales of the original title, released in 2007, over the same time frame, Ubisoft said. Both games have received critical acclaim for their immersiveness, backed by graphical and audio artistry.

Assassin's Creed 2, which puts players in control of an assassin in Renaissance-era Europe, has a rating of 92 out of 100 on review aggregate website Metacritic.

Analysts expected sales to be lower because of the tough economic climate and because Assassin's Creed 2 is targeted at the same audience as Activision's Call of Duty: Modern Warfare 2, which was also released earlier this month.

Modern Warfare 2 has smashed all sorts of records, with more than 4.7 million units sold in the United States and United Kingdom in its first day and revenue topping $310 million U.S.

With a price tag of around $60, Assassin's Creed 2 is expected to have pulled in close to $100 million U.S. in its first week.

Wedbush Morgan analyst Edward Woo told website TG Daily that Ubisoft's game is on track to sell six million units by the end of December.

The game was developed mostly by Ubisoft's Montreal operation, which is one of the largest game studios in the world. The Montreal studio produces most of the French companies top hits, including several Tom Clancy games.