The first non-Angry Birds game in more than two years from Rovio Entertainment has hit No. 1 on the download charts.
Rovio, the maker of Angry Birds games - in which players use a slingshot to attack pigs who steal the birds' eggs - has been valued by analysts at $6 billion to $9 billion.
Rovio's new puzzle game, Amazing Alex, became the No 1 paid app on the key United States app store shortly after the launch.
It could mean that the Finnish startup is more than a one-hit wonder.
Amazing Alex is a physics-based game that features challenges that curious boy Alex has to solve.
"Launching new franchises has turned out to be tough for even the most successful app vendors, but Amazing Alex reached the Number One position in the iPhone Paid App chart in eight hours," said analyst Tero Kuittinen from Finnish mobile firm Alekstra.
"This is the fastest time to hit the Number One position in America - without help from being a sequel, a movie tie-in or an extension of an existing brand." he said.
Rovio, founded in 2003, became a global phenomenon after it launched Angry Birds for Apple's iPhone in late 2009 and has since focused on turning out sequels of the original hit.
This has helped it to remain at the top of gaming charts, with more than a billion downloads, and it had 200 million monthly users at the end of 2011, compared with US based Zynga's 240 million.
Rovio's sales jumped 10-fold to $100 million last year as gamers flocked to download its titles and the firm has said it was considering going public.
Last year, Rovio raised $42 million from venture capital firms, including Accel Partners, which previously backed Facebook and Baidu, and Skype founder Niklas Zennstroem's venture capital firm, Atomico Ventures.
Rovio's valuation places it roughly on par with Nokia valued at €5.8 billion at yesterday's closing price.