First of all, I'll happily say I'm loving the game. If I could find matches I'd be playing more! (but that's not my issue)
As a very good Antagonist, nothing is more frustrating than getting the team down to 1 left to win then the Host quits, which resets the whole checkpoint back to full lives! To make it worse, that host can then rejoin the game and repeat so you can never win. 'Mr LT Nice' just did this again to me with their friends.
This is extremely gamebreaking in my opinion and ruins such a great concept. I do have a few other, less important issues. One of which occurs when 2 people try to grapple at the same time. It seems that whoever presses it last gets the kill, as the first person's animation ends first, making them vulnerable. To me it makes no sense to be punished for having better reactions. I think a good idea would be some form of neutral outcome wher both grapplers push each other back. I have so many gameclips where I would win the game but get denied by a slightly slower enemy.