Interesting details that aren't immediately apparent

[scionicspectre]

After looking through the concept art, I noticed a few details about enemies that I wouldn't have seen otherwise. For instance, the Dreamrunners' heads appear to be spider-like creatures, which could explain why they wear masks.

Is there anything else you've noticed in the game that isn't apparent at first? I'm hoping this thread could be a good place to collect these little nuggets of information.