Gave the four-player co-op a spin last night with a bunch of strangers and it went really well (especially since they were all on mics and I wasn't).
The in-game emotes and pre-made text messages are absurd and hilarious. At one point all hell is breaking loose--giant ants are raining down from a half dozen alien ships--and one of my teammates asks, using the in-game system, "Can we talk about this later?"
I don't know why, but this absolutely killed me. I wanted to respond with "I'm just going through some things. I'll text you." but all I could find was WULARG! which, honestly, was even better because it was a vocal emote. WULARG! became my battle cry.
I'd also like to say that whoever came up with the songs the soldiers sing is brilliant. This game is so great. Now to fix the font scaling issue