There’s also a Windows 10 version planned and you only need a single purchase.
Dodge Roll’s team has confirmed that Enter the Gungeon will be released on the Xbox One on April 5th. Thanks to the Xbox Play Anywhere program the gun-full roguelike shooter will be available on Windows 10 as well and you need only a purchase on one of those platforms to play on the other.
If you aren’t familiar with Enter the Gungeon, the game includes dozens of weapons including guns that shoot guns and other much trickier arms. The titular dungeons you visit are generated every time you visit them so the replayability is awesome here. You can check the PS4 video below to get a better idea: