Here's a fun sneak peek at the animated Assault Exo (not yet lit).
Why are there moving hull parts? They really off-put me, because I don't understand why they'd move and make said hull weaker.
Real reason? Because they look awesome, and still is boring visually.
If you want a fake in-game-world reason I'm sure I can make one up, too. But suffice it to say there are a lot of constituent parts on these, and armor is not their best thing. This could be part of the propulsion system, part of the computer system sensors, part of the reactor venting system, even. It could even be decreed that it is some sort of thing that messes with the computer vision algorithms of the robots. I don't think what is going on there is outside the realm of sci-fi plausibility, and it really does look vastly better.
Gameplay-wise, it also serves a purpose: alerted robots are animated and alive-looking, whereas non-alerted robots collapse down into a less saturated, non-animated shell. So we don't have to do something like put a cheesy "ALERT!" or "!" or whatever over top of them. Very efficient.
Anyhow, I'm super proud of it.