Actually I am playing this game since release in single player and in coop with mixed groups (2-4 players).

The main issue is that the game cannot manage the positioning of the players, most of the time every player sees the other characters standing on different positions. For example while player 1 sees his own character 5-10 meters away from some mobs, the other players see him surrounded by a horde of enemys . So on many occasions this player suddenly dies but he couldn't see the enemys around his character.

Additionally some things don't work in coop like they do in single player. The regeneration per class resource spend shows a healed amount as floating green number and also in the lifebar of this character, but as soon as he gets a hit, no matter how high the hit is, the lifebar just resets back to the amount of life the character had before the heal applied. For example with my crusader I am on ~1000 hp (20%), perform two jetpack jumps and heal round about 2000 hp  to ~3000 hp (60%) and I get a hit of 200 damage, my life resets back to 1000 hp and additionally it seems I take the 200 damage on the resetted amount so i'm on 800 hp. 

This is a major issue because several builds need the selfheal to survive and combined with the first issue this makes the game absolutely frustrating to play in coop.

The main reason to play this game for the most players I know is coop, so this should be addressed as soon as possible, maybe take some more time for season 2 (the next raise in PR and lvl cap within 3 Month is to much) and fix these bugs. 

Sadly it is still an issue, even the devs said they made improvements. 3 of my friends already refunded the game via steam, because they wanted to play the game mainly in coop. Today I tried to play coop with an other friend, and on the first 7 attempts we got the message, that the server does not respond. After that we could connect and play for 3 minutes with lags, but than we got an timeout and a disconnect.

As much as I lof the game and the setting, it sadly feels like an alpha or an early beta build.

I hope, for the sake of the game, that there will be updates soon. Because I think, in its currents state, many people gonna abandon this game.

The Emperor Protects!