Pokemon Sleep took so long to release because its developers had a hard time playtesting a game that could only be played once a day.
As revealed in an interview with developer Select Games and Famitsu (translations via Automaton), the team working on Pokemon Sleep had to take extra time developing the sleep tracking app due to only being able to playtest the game once a day - when humans would naturally get a full night's sleep.
Select Games' Keisuke Miyagawa told Famitsu: "We struggled with testing the game because you have to sleep to do so. Basically, we could only do one test run per day," Miyagawa explains, "while it’s technically possible to proceed by using temporary sleep data, there is always a possibility of something unintended happening when actually sleeping, so we tried to have the testers sleep for real as much as possible."
As well as this, the team at Select Games - who worked alongside Pokemon Go developer Niantic and The Pokemon Company - also had to deal with localizing Pokemon Sleep into eight different languages and simultaneously release the compatibility for Pokemon Go Plus+. This, along with the playtesting problem, is why we had a four-year wait for Pokemon Sleep.
Fortunately, we now live in a post-Pokemon Sleep world which has revealed some surprising truths about ourselves. For example, very quickly after its launch, Pokemon Sleep fans learned that the game is recording their farts while they sleep. Hey, at least it means you're definitely relaxed whilst catching those Zs.
There's also been some strange suggestions as to how to get ahead in the app. For instance, one Japanese outlet suggested that Pokemon Sleep players take sleeping pills to get better at the game. As you can imagine, this tip did not go down well, and has, thankfully, since been removed from the website in question.
Enjoying Pokemon Sleep? Take a look at our best Pokemon games list to find out what our favorite pocket monster title is.