Expression, colours and contrast
I think it came out great. I really like the overall colour scheme and the contrast. They create an almost completely unemotional atmosphere, that goes pretty well with the setting.
I also like how you gave them different facial expression while they only have eyes. Most bots look dull or bored and to me #F6 and #F7 look almost sad, while the main char looks surprised.
Not sure if this is some kind of helpful feedback, but when I look at it in full size I always imagine some kind of loud electric buzz emanating from those glowing "control orbs".
Overall, good job of course.