Technical issues abound
I played through all three missions with another reviewer online, which made them about ten times as fun. But it also highlighted the fact that even months after the game's release it's still plagued by rampant technical issues.
My partner was consistently kicked at the beginning of every mission, so I had to get to the first checkpoint, quit, and then invite him back to my party and load the level up again. Only I could see or hear the mission briefings, no matter who hosted. He and I were both kicked out at various other times, and the game even froze on the loading screen indefinitely at one point.
It's frustrating to be wrestling with shit like this, especially this long after a game's release.