Finnish game maker Rovio launched Angry Birds 2 on Thursday, a sequel to what the company claims to have been the most downloaded mobile game series of all time.

"With new towers to topple, pigs to pop and missiles to master, Rovio is thrilled to announce the launch of Angry Birds 2," the company said in a statement.

Angry Birds was a worldwide success after its release in 2009, but the game started losing its appeal in 2013 and Rovio is now trying to swoop back from a sharp drop in profits.

Earnings before interest and tax slumped to 10 million euros ($11 million) last year from 36.5 million euros in 2013.

Last December Rovio cut around 110 jobs, almost one in six of its workforce, and shut down its game development unit in Finland.

In 2014, Rovio's overall sales fell by nine percent, even though income generated by new versions of the gaming app grew by 16 percent.

Rovio said the game's visuals and gameplay have been overhauled for the sequel.

"Design technology has evolved dramatically since the original game launched in 2009. With Angry Birds 2 we wanted to bring a level of expressive depth and detail seen previously only in a console game or animated series," co-founder Niklas Hed said in the statement.

The company is also working on a 3D feature film set for release in May 2016.

In addition to its games, Rovio also sells Angry Birds merchandise and runs Angry Birds theme parks in several countries including Finland, China and Spain, and publishes children's books in dozens of languages.