Recently on my quest for a good Battle Royale game on Linux I came across surviv.io and I was impressed, since then the developers have continued to improve it.
Since I last wrote about it, they've added in smoke grenades, dual pistols, a SCAR-H assault rifle, a bank building to loot, a police station full of loot and plenty of optimizations resulting in a game that's actually quite a bit smoother than it was before. The stuttering I experienced sometimes before, has practically gone.
They're still working to add in rivers, cities, melee weapons and an account system so there's plenty more to look forward to.
I'm still surprised at just how addictive the game is, considering the lack of good Battle Royale alternatives, for now it fills a small hole for me. The fact that you can join up with your friends, simple by sending them a link to join your party is pretty awesome.
If you haven't given it a chance yet, be sure that you do, it will surprise you.