"Project X" with 400-Person PvP Arena mode is Going to Beat PUBG, Fortnite — Battle Royale and others

Automaton's 'Project X' is a 1000-player MMO with its own spin on PvP arena combat.

UK-based studio Automaton Games is making a tactical shooter MMO that will feature up to 1000 players, with a world that will be shaped by their actions. This game has not been officially announced yet, nor does it have a name (it's been codenamed 'Project X'), that includes 400-Person PvP Arena mode.
Game developer announced that it had raised $10 million of investment to make this game. 
 

Project X is built using SpatialOS, that means  'massive scale', 'meaningful persistence' and 'rich simulation' as three major advantages of what its technology offers. In that game, players can build an airship, crash it somewhere, then another player can come along later and see the wreckage, as a piece of living environmental storytelling—that's a small, neat way of demonstrating what is meant by 'meaningful persistence'.  Also a cloud-based technology is used to help developers get around the traditional hardware restrictions of game development.  

The game is described as a "full MMORPG", with five progression tiers of weapon and armour, as well as customisation and perks. Players will pass parties in the world that could be two people strong, or up to 25, with a kind of risk/reward system to balance the game. On the unlikely event that someone's on a 1000-strong killstreak, other players will be alerted that this is going on, plus there will be a bounty system to keep people in check. It's players policing each other, in a sense, with ongoing balancing provided by the developers. Tanks are mentioned as another, less drastic killstreak bonus. 
The game also boasts a 'machine learning-driven quest and events system'. You take on RPG-style quests, and based on which factions you ally with, how you choose to complete these quests and what your clan does, this will apparently inform how the story progresses. You can ignore the MMO stuff if you want and play the game solo. 

And in conclusion, Game developers want global changes to the whole simulation and environment.