I've played for 3-4 hours today, and my overall thoughts that I keep repeating to my self is "turdy gameplay".
The ideas of the things in the game are good in general, but the implementation is just so poor in that I honestly just can't stand most of it, if this game ends up as a buy game then I wouldn't dare buy it if these features and mechanics stick into the final product.
Antagonist is a good idea in concept, I remember having this in a game called Global Agenda in which is was an optional PvE mode and you got extra rewards for the added difficulty of having a player also trying to kill you. The problem here though is that you're forcing a PvP concept into a PvE mode that's already very difficult as it is, especially when you're playing with random people we have no communication with.
I have no idea if the Antagonist has infinite lives or what, but there's nothing more boring than being killed by someone pressing E, it's bad enough that some specific enemies do it to you in which you're forced to run away like an idiot and keep dropping some bullets behind you, but killing them is the most un-fun thing I've ever had to do, they charge at you for all eternity until they hit a wall or something to jump up.
Antagonist players on the other hand will be barraging into you when a bucket load of enemies have spawned (which is already far too often as it is and with no set areas after you've already cleared the area) and either meleeing you or just press E if its from the side with no time for them to reliably react, but even then when the game is lagging with a poor connection you can guaruntee that the person trying to grapple you when get you regardless.
When you run out of lives and need to survive the time limit to come back again, the huge problem comes in when it's possible to deal with the AI during the given period if you play smart, having an enemy player makes this virtually impossible to survive due to the map layout, how aggresive the enemy AI are, and that melee/grappling is impossible if they're starting directly at you.
What I honestly hope gets taken out of this game is grappling, it's 100% not fun to die to it, it's barely a little fun to actually pull off considering how the AI will always melee you if you're directly infront of them, meaning it's mostly an assasination tool from the side/behind, what I've found is if something is incredibly un-fun to die to and it's not removed, players will simply leave the game, this is even more of a given when Shae just makes her self virtually invisible to you and jumps you with a grapple, result? frustrating and not fun.
This brings me onto my second point here, Antagonist should be its own mode, there needs to be a strict PvE only mode, and a second PvE mode that allows players to come in as an Antagonist at any point in the match, you will be hard-pressed to find people like me that will play the game if Antagonist is there by default, because I don't enjoy dying to heavy cheese gameplay, especially when that cheese is lagging.
TL;DR:
Antagonist needs to be in a seperate/optional PvE queue, many players do not like dealing with odd modes like this when the game is especially not balanced for that kind of gameplay.
Grappling should be reviewed and possibly taken out of the game, it's very un-fun to die to, by both Antagonist players and AI chargers, it's a no-skill ability that kills you while the enemy that grappled you is fully immune to damage while the animation is happening, leaving to counter play for an obviously stupid ability.
P.S I've been unable to find any difficulty selection, this could really be a problem when the AI are very aggresive and deal so much damage to players from both shooting and meleeing, technically speaking every individual AI has a very good chance to kill a player, average/casual players will not enjoy dealing with what I'm assuming is the default difficulty.