Players will be able to opt into (or out of) player-versus-player and player-versus-environment gameplay as they choose, much like MMOs do. There’s still more to learn about how PvP will work, but Bethesda Softworks has signaled that if players don’t want to take on human-vs-human combat, they won’t have to.
Some of the details to emerge so far include a “bounty system” which levies a price on the head of players who behave aggressively. PvP’s balancing is still being tuned with the ideal of curbing grief behavior while still leaving room for dramatic struggles.
Being killed in PvP (or PvE) for that matter, will never result in progression loss for a character. In PvE, once downed they’ll take a knee, which they can then be revived or knocked out for good (again, like some MMOs). Players killed in action can pick a respawn point and rejoin the game.
For PvE, users can expect to deal with a slew of beasts, mutants, ghouls, deathclaws and the new monsters unique to this game. One is a “Scorchbeast,” an enormous, boss-level mutated bat-like monster that can fly. Scorchbeasts are tied to one of the more intriguing — and difficult — PvE goals, the Nukes.
Four different nuclear missile sites will be located on Fallout 76’s map, from which players can arm and launch a nuke. This is accomplished by obtaining all of the missile keys for a site, which are dropped by NPC enemies in the world. Nuking a site creates “rare and valuable resources” at that location, along with more powerful monsters.
Canonically, nuking a site involves sealing the nuclear fissures in the grown where they are spawned. As far as how this affects other players, there will be a warning before one comes in. Bethesda Game Studios does not intend nukes to be a kind of PvP ultimate strike on others’ bases. And by the way, there will be no offline base raids on other players. When they’re not in the game, neither is their base.
Update, 7/6/18: In an interview with the Italian publication Multiplayer, [Todd] Howard said that Fallout 76 will feature fast travel — somewhat critical given the size of the map — and suggested that low-level players may not be killed in PvE play to prevent “spawn-camping” or other poaching behavior. “Maybe we will change this rule,” Howard said, so that’s not a confirmed boundary for PvE. But Bethesda Game Studios at least seems mindful that it has to take steps to protect newcomers or limit griefing behavior.
Update, 8/11/18: At QuakeCon 2018, Howard said that while human players can hunt down and kill other humans, there are consequences. Players who kill others will get a “wanted murderer” designation that exposes them on the mini-map to other human players, with a bounty paid out of the offending player’s cap total if they are killed. Further, players killed by another human player will be able to seek revenge for double the usual payoff. “We turn the assholes into interesting content,” Howard said.