Pokémon's new mobile game lets you play while sleeping

Pokémon's first mobile phone game encouraged people to get outside and walk around to catch them all. Now the company wants people to improve their sleeping habits.

Pokémon Sleep was announced during a livestream on Wednesday (NZ time), to a very mixed response.

Pokémon Go was wildly successful and quickly became a cult hit, luring in more than just the traditional devoted Pokéfans. It's played by walking around to find different Pokémon, hatch eggs, and to get free items in the game.

Information is sparse around Pokémon Sleep, which won't be released until next year.

"In 2016, Pokémon GO turned the simple act of walking into entertainment, making the entire world into a game," Pokémon announced on Twitter.

"We’re about to do it again, Trainers - this time, for sleeping."

During the livestream Tsunekazu Ishihara, the Pokémon Company's chief executive, said the aim is to "reward good sleep habits as part of a healthy lifestyle".

The sleep tracking will be done by a new device called the Pokémon Go Plus+ (pronounced 'Plus plus'), a Pokéball-shaped item with an accelerometer to track sleep data and act as a pedometer.

Its immediate reception online was mixed, with some users speculating it was a joke.

"Also Me: Looks at clock and sees it's almost 3am when I know I have to be up at 7am. Me again: Finally a Pokémon game that'll be a challenge," Twitter user and online gamer Matt Bragg tweeted.

User Hikaru Kagi was more sceptical.

"This sounds weird, not too sure what to feel about this one," he wrote.

Pokémon Sleep wasn't the only game to be announced during the livestream.

A sequel to Detective Pikachu - which was turned into a live-action movie starring Ryan Reynolds this year - will be released on the Nintendo Switch, while another app called Pokémon Masters is also being developed. The fourth announcement is for Pokémon Home, a cloud service that appears to let people transfer their Pokémon between the various games.