OSAKA -- Though "Super Mario Run" has lifted Nintendo's profits less than many had hoped, Mario remains the protagonist of the company's mobile strategy, with a jump to a new smartphone platform highlighting the game producer's main goal of expanding its fan base.

The first smartphone game in Nintendo's beloved "Mario" franchise debuted on Google's Android mobile operating system Thursday. As with the Apple version released in December, part of the game is available for free, and the rest can be unlocked for 1,200 yen ($10.81), or $9.99 in the U.S.

"Super Mario Run" was greeted with much fanfare after its surprise announcement last year at an Apple event. The game enjoyed a strong start in the App Store, topping download charts in several countries. Yet it was less of a moneymaker for Nintendo than might have been expected, due to the pay-once-and-play model. Revenue from the game "did not meet our expectations," Nintendo President Tatsumi Kimishima said.

The Android release is expected to sharply expand the user base for "Super Mario Run," but the same pay-once model means it is unlikely to provide a big boost to earnings.

Nintendo's smartphone cash cow is instead "Fire Emblem Heroes." "Heroes" is a "freemium" game that lets players pay to unlock random characters -- a format known in Japan as gacha. The smartphone game market is fiercely competitive, and even the use of popular characters does not guarantee success. Yet "Fire Emblem Heroes," an entry in the popular "Fire Emblem" series of strategy role-playing games, led sales rankings from its debut, underscoring the power of Nintendo's library of intellectual property.

Even so, Nintendo has no intention of switching focus to freemium games. "'Heroes' is an outlier," a senior company official said. "We honestly prefer the 'Super Mario Run' model."

Nintendo aims to do more with its smartphone games than make money. The Japanese company seeks to bring its games and characters to a wider audience and create synergy with game consoles such as the new Switch.

The problems with the gacha model, such as the large amounts of money often required for success, risk undermining the value of Nintendo's characters, which in turn could dent the company's bread-and-butter console-game business. Nintendo's apparent goal with smartphone games is to attract more users even if the company loses out on some profits in the process.

Alongside the Android launch of "Super Mario Run," Nintendo expanded the free-to-play portion of the game and improved issues that had drawn complaints from players. The game's true value will be measured by how much it expands the ranks of Nintendo fans and helps sales of the Switch.