Back in March 2016, Nintendo released its first-ever mobile game, Miitomo. Now, just two years after it launched, the company's first foray into smartphone gaming is coming to an end: Nintendo is shutting Miitomo down on May 9.

Many fans of the Japanese gaming legend expected its mobile debut to feature an iconic character such as Mario or Link. Instead, we got a 'social app' rather than a game, one that involved creating customizable avatars called Miis, playing mini-games, and responding to questions and sharing the answers with friends.

Following its launch in Japan, Miitomo soon arrived in the US. A month later, it appeared that the game's initial poor reception, which caused both Nintendo's and developer DeNA's shares to fall, hadn't affected its popularity. A survey showed that Miitomo had 4 million monthly active users who spent around 8 minutes a day in the free app, which was bringing in $40,000 of daily revenue from in-game purchases.

But players soon got bored of the game's limited appeal and started to drift away. Nintendo hasn't said why it decided to kill the app, but dwindling user numbers are likely to have been a major factor.

Sales of Miitomo coins, which players used to buy outfits for their Miis, ended yesterday. But until the service closes on May 9, Nintendo is offering daily login bonuses of 2,000 Miitomo coins and five game tickets. Those who want to keep their Mii avatars can transfer them to their Nintendo account.