Pokémon Sleep, a game in which players go to bed in real life to win, is rocketing up the App Store charts. The app is now sixth in Apple’s charts, suggesting that makers The Pokémon Company may have found a way to replicate some of the success of their previous hit Pokemon Go. To play the game, people download the app onto their iPhone – or use a separate, paid-for accessory that the company says can be used to track sleep as well as make it easier. Once that is done, users mostly play by going to sleep. When they wake up in the morning, they will receive information about their sleep patterns – how long they slept, what kind of sleep that was, and whether players made any noises during the night – and receive rewards of Pokémon that will be caught based on that data. The game has received some negative reviews: on the iOS App Store, one player called it “deeply flawed and predatory”, criticising the fact that tracking sleep with the iPhone app means sleeping with it and leaving the screen on. While players can use the Pokémon Go Plus +, which has been given a confusing name presumably to separate it from the existing Pokémon Go Plus, that costs $60. It also received a critical review in The Verge, which said that while it was “incredibly cute”, it came with some drawbacks, including the fact that it requires players to undertake dull tasks during the day and offered few meaningful ways to actually improve sleep. Nonetheless, the game appears to have proven incredibly successful on the iPhone’s App Store and Android’s Google Play Store, where it has been downloaded millions of times. The game comes amid a growing interest in the benefits of sleep, and the technology that can help promote it. Multiple wearables such as those made by Apple, Garmin and Whoop all track the sleeping habits of their wearers, and other companies have promoted cooling and massaging technologies that are aimed at helping people get more restful sleep.