They turned everything up to 11 is what they did. I was in a fireteam, all 400+ and it was ridiculous. Halfway through the first level and we're not killing stuff quick enough. There's some brutal buffs for enemies like shielded wizards blasting you from halfway down the street while a Tormentor is tormenting you and your fireteam. Screebs are appearing from nowhere and you've got that blast debuff thing where if your shields break, you're basically -blam!- toast. I got behind the wizards, killed them as my team mates finished off the Tormentor then immediately two yellow bar Shriekers spawn, one right above my head. I go to slip round a corner but too late, shield toast and a 15 second timer. I see my team mate trying to get to me but his shield is gone too so he can barely get to me. I see about 20-20 trash mobs smashing the crap out of the thing in the middle. It was a total nonsense from start to finish and I'm not even going to bother with it again.