In Short: Fortnite is officially out of closed beta for Android, and now anybody can download the game. The kicker is that this does not mean that compatibility issues magically go away; if you have an older or weaker device, or perhaps a device that the team has been having trouble getting the game working on, like a Motorola device, then this doesn't change much for you. Additionally, nothing changes for those who got an invite and got into the closed beta, or had a Samsung device that was able to play before. The game is also still not available through the Play Store, nor will it ever be; you'll have to head to Epic's website, linked in the company's Tweet announcing this development.
Background: Up until now, only select newer Samsung devices could play Fortnite with no complications. Many a device was and still is left out in the cold due to compatibility issues, and even if you had a compatible device, you had to have gotten in on the trend early in order to score a closed beta invite. Those who had both a closed beta invite and a compatible device could still run into unforseen or even known problems, despite Epic's best efforts. It's no stretch to say that the mobile port of this popular console game is very much still in the early stages of development, and those who choose to play on almost anything but a Samsung device will find that out in short order. Samsung owners, meanwhile, will be delighted to know that their manufacturer of choice actually worked directly with Epic to help get the port off the ground, making those phones the best ones to play on for now.
Impact: Now that the game has gone open beta, you'll no longer need an invite of any sort to download the installer APK and download the game data. Getting into a round, however, still won't happen if Epic has not yet gotten around to dealing with any compatibility issues your particular device of choice may have. Even so, you can always keep the installer APK handy, or even install the data ahead of time so you don't accidentally download another app into the space that you would have to use for Fortnite. That way, when the update enabling compatibility with your device does roll out, you'll be able to take it quickly and jump into a game within minutes of your device being announced and added.