While not a retro game itself, I was playing Atomfall just now and came across this metal head in the robotics section, which is a lovely little hidden reference to a late entry in the Bitmap Brothers catalogue, Z.

Z was a decent game back in the day, and yet another example of the Bitmaps showcasing their skills at being able to produce top quality games in whatever genre they chose.

Rebellion gained ownership of the Bitmap Brothers games a few years ago, so it's not out of place in Atomfall, but still a nice nod to one of British gaming's most beloved studios.