Was in a team that took down a Teralyst (the big fellas) today - it’s actually a lot of fun, quite hectic. But you can see the need to beef up the Operator, we took ages and only just got it down before the dawn. Cell composition was random, but we had a Trin, a Harrow, an Ivara and my Titania.
Basically you need to be in Operator mode to take down the Teralyst’s shields, then in warframe mode you sequentially focus down the knees, shoulders and head in phases. Each time you get one of those parts, the Teralyst falls (and spams a huge AoE emp aura type thing that can one shot a frame, so you have to get out of the way) then it disappears and respawns somewhere nearby on the map, and you have to go through the shields again and focus down another part (note, Shield Disruption aura is useful here, apparently). You do need a Sortie-capable team to take down the parts quickly, they’re hit point bags. (Harrow’s crit buff was really useful here, especially on the last point, the head).
There are phases with the Vomnalysts (the wee fellas) too - some of them attack, some heal the Teralyst, not quite clear what’s going on there, but basically if you see lots of Vomnalysts around the Teralyst just kill them with your Operator (and pick up their drops, they’re for the Quills standing).
At this stage my Operator was dying a fair bit but you respawn quickly in the frame, and it’s all fairly fluid, as well as fluid switching between frame and Operator.
The graphics and audio fx are very impressive and the thing spams uncounted varied AoE attacks, you do feel like you’re fighting a giant Kaiju thing.