Every gamer loves going back to their roots and playing the classics. With the rise of game console emulators, players have been able to get their hands on originals without sacrificing 'quality' or rebuying official PC ports. Of course, it's safe to say that the legality of using emulators can be called into question. Microsoft's answer? Don't allow them at all.
According to a change in the Windows Store policy (via Windows Central), apps that attempt to emulate a game system are no longer allowed. The policy update was published on March 29, and developers of the Nintendo emulator NESBOX recently complained that their app has been removed from the Windows Store.
— NESBOX (@nesboxcom) April 4, 2017
The change was applied to the under the Gaming and Xbox section as rule 10.13.10 stating "Apps that emulate a game system are not allowed on any device family." Microsoft is no doubt attempting to protect their Store and devices from any legal issues pertaining to the grey area of emulator downloads, so the new policy shouldn't come as a surprise.
Still, the NESBOX developers won't let that get them down. Instead, they open sourced the emulation core to GitHub and will further support their app without the help of Microsoft's UWP. But NESBOX isn't the only emulator on the Windows Store as of today: Snes8x, a popular Super Nintendo emulator for Windows phones hasn't been removed as of yet. It is likely we'll see an exodus of such apps on the market in the weeks to come.