In the Nuclear Winter mode, 52 players from Vault 51 are separated by ZAX computer systems into four different squads. These squads must then fight it out to be the last vault dweller standing, while a ring of fire closes in around them, all in the hope of finding the next Overseer.
In an official blog post, Bethesda announced that they had been “blown away by the reactions and responses we’ve been seeing all week to Nuclear Winter. It has been so amazing to read all your experiences and see everything you’ve been sharing.”
As a result of the good feedback, the pre-beta of the game, which was only supposed to run for a week, "will remain on and continue to receive updates, so keep sharing your feedback.” This appears to mean that the pre-beta will remain live beyond the free Fallout 76 trial which is currently available until June 17. If you’re looking to give Fallout 76 a try and wouldn’t mind trying a new battle royale mode then now is the time to do it. The best part? Any progress made in the trial will carry over to the final game.