After almost two years of waiting, the big day is finally here for Nintendo Co. and its first game for smartphones, "Super Mario Run."

The release for Apple Inc.'s devices on Thursday is the first full test of what the Japanese game maker can achieve after years of eschewing the thriving mobile app market. While Nintendo gave a hint of its potential with the success of "Pokemon Go" earlier this year, that title was only partly its own creation.

"Super Mario Run" was developed mainly by Nintendo, with some assistance from partner DeNA Co. Expectations have swelled since the Kyoto-based company announced a strategic shift toward embracing mobile in March 2015, adding almost $20 billion to its market value. Yet amid the euphoria, some are already discovering holes in execution. Macquarie Securities analyst David Gibson finds it puzzling that the game requires an internet connection and worries that the $10 price tag for the full version might be too aggressive, especially for users in developing countries.